BIL255 Exam I Fall 1998

BIL255 Exam I Fall 1998 - PreMed411.com ANSWERS TO FALL 98...

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Unformatted text preview: PreMed411.com ANSWERS TO FALL 98 TEST 1 BIL 255 Dr. Herbert: ANS 1: 8 12 20 26 32 37 38 40 <--question #’s ANS 2: 3 13 15 18 22 23 27 36 ANS 3: 4 16 17 19 24 29 30 31 ANS 4: 6 11 21 25 28 34 35 39 ANS 5: 1 2 5 7 9 10 14 33 ANSWERS TO FALL 96 TEST 1 BIL 255: ANS 1: 2 3 13 15 16 26 30 39 ANS 2: 1 7 9 14 19 22 24 25 28 29 34 40 ANS 3: 4 5 6 8 12 18 21 32 35 38 ANS 4: 10 11 23 27 31 33 36 ANS 5: 17 20 37 ANSWERS TO SUM 96 TEST 1 BIL 255: ANS 1: 1 3 21 25 28 34 36 38 41 42 ANS 2: 2 5 9 24 35 39 43 46 50 ANS 3: 6 10 11 17 18 20 22 33 37 44 45 49 ANS 4: 7 8 14 15 23 26 31 32 40 48 ANS 5: 4 12 13 19 27 29 30 47 ANSWERS TO FALL 94 TEST 1 BIL 255: ANS 1: 3 7 10 11 19 26 30 38 42 46 49 ANS 2: 4 6 12 15 18 20 28 31 34 41 ANS 3: 9 14 16 21 25 33 36 39 45 48 ANS 4: 1 4 22 24 27 29 32 37 43 47 50 ANS 5: 5 8 13 17 23 23 35 40 44 Bil 255, Cell Biology - Fall Semester - First Examination - October 6, 1998 Form 1 1) What is GRP78? 1. carbohydrate 2. a non-protein group which binds iron in hemoglobin or myoglobin. 3. a non-competitive inhibitor for one of the enzymes in glycolysis. 4. hydrophobic non-protein materials used to denature proteins in the laboratory. 5. none of the above answers are correct. 2) A colleague tells you that a particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics and that at a substrate concentration of 3mM, the reaction velocity is one-third of maximum. What is the Michaelis constant, KM? 1. 1mM 2. 2mM 3. 3mM 4. 4mM 5. none of the above answers are correct. 3) A colleague tells you that a particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics and that at a substrate concentration of 3mM, the reaction velocity is one-third of maximum. At what concentration is the reaction velocity one-quarter of maximum? 1. 1mM 2. 2mM 3. 3mM 4. 4mM 5. none of the above answers are correct. 4) A colleague tells you that a particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics. You run this reaction with just enzyme and substrate and then repeat your experiment with some mystery substance added. When you add the mystery substance, you find that the maximum velocity of the reaction remains the same. But, the effective KM is smaller when the mystery substance is added as compared to the KM measured without mystery substance. Which of the following best describes the mystery substance? 1. competitive inhibitor 2. noncompetitive inhibitor 3. activator 4. the mystery substance is just more of the substrate. http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (1 of 8) [8/29/2000 1:11:49 AM] 5) Let's suppose that life first appeared around volcanic "vents" deep under the ocean's surface. Which of the following best characterizes or identifies the first cells to appear around these "vents"? 1. heterotrophic eukaryotes 2. heterotrophic prokaryotes 3. chemoautotrophic eukaryotes 4. photoautotrophic prokaryotes 5. chemoautotrophic prokaryotes 6) There is one type of amino or imino acid in which the residual side chain forms a covalent bond back to the amino or imino nitrogen on the alpha carbon. What is an example of this amino or imino acid? 1. cysteine 2. glycine 3. alanine 4. proline 5. cytosine 7) Which of the following best describes mercaptoethanol? 1. Disrupts hydrogen or hydrophobic bonding. 2. An unusual type of amino acid which puts kinks or bends in protein chains. 3. The light sensitive purple pigment used to capture light for photosynthesis in some primitive autotrophs. 4. Mercaptoethanol competes with ethylene glycol as a substrate for alcohol dehydrogenase. 5. A powerful reducing agent. 8) What sort of bonds might be found between molecules in gasoline or oil? 1. hydrophobic bonds 2. ionic bonds 3. hydrogen bonds 4. disulfide bonds 9) Which of the following is an allosteric inhibitor for aspartate transcarbamoylase? 1. ADP 2. DHAP 3. ATP 4. UDPG 5. CTP 10) A particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics. You make a plot of Vmax/V vs. 1/[S]. You draw straight line which best fits this data and determine that the intercept of this line with the Vmax/V axis is 1.0 and the intercept with the 1/[S] axis is -2.5mM-1. What is Vmax? http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (2 of 8) [8/29/2000 1:11:49 AM] 1. 1.0 mM/sec 2. 2.5 mM 3. 0.4 mM/sec 4. 0.4 mM 5. none of the above are correct answers. 11) A particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics. You make a plot of Vmax/V vs. 1/[S]. You draw straight line which best fits this data and determine that the intercept of this line with the Vmax/V axis is 1.0 and the intercept with the 1/[S] axis is -2.5mM-1. What is KM? 1. 1.0 mM/sec 2. 2.5 mM 3. 0.4 mM/sec 4. 0.4 mM 5. none of the above are correct answers. 12) ATP is often spoken of as a "high energy molecule". Which of the following is most accurate with respect to why ATP might be considered a "high energy molecule"? 1. Half of the Gibbs' energy released when ATP is dephosphorylated comes from the large entropy of the resonant forms of ADP and phosphate. 2. The covalent bond between the terminal phosphate and the rest of the ATP molecule permits sharing of more electrons than a normal low energy covalent bond and thus is stronger. 3. Removal of the terminal phosphate from ATP releases much more energy than release of a terminal phosphate from GTP, UTP, etc. 4. The phosphate groups on ATP are positively charged and thus repel each other. 13) Which of the following is most accurate with respect to 6-phosphofructokinase? 1. The enzyme which permits glucose units to be added to a growing starch chain. 2. An allosteric enzyme used in glycolysis. 3. 4. The immediate product of this enzyme is lactic acid. Cells which don't do lactic acid fermentation don't have this enzyme. Acetyl-CoA is involved in reactions catalyzed by 6-phosphofructokinase. 5. Not an enzyme - 6-phosphofructokinase is a high energy phosphorylated form of fructose. 14) You are given some cells and determine that they have mitochondria and two haploid nuclei. From which organism did they most likely come? 1. a dog 2. a mango tree. 3. a mycoplasm. 4. Giardia 5. None of the above are correct answers to this question. (This answer was added - The original http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (3 of 8) [8/29/2000 1:11:49 AM] exam had no correct answer - Thus, everyone was given credit for this question.) 15) You are given some cells and determine that they have mitochondria and chloroplasts. From which organism did they most likely come? 1. a dog 2. a mango tree. 3. a mycoplasm. 4. Giardia 5. These cells could have come from more than one of the organisms listed above. 16) You are given some cells and determine that they have no mitochondria. From which organism did they most likely come? 1. a dog 2. a mango tree. 3. a mycoplasm. 4. These cells could have come from more than one of the organisms listed above. 17) Which of the following is the most satisfactory explanation to why ammonia would not be a good substitute for water in living cells which may exist elsewhere in the universe? 1. Ammonia is a hydrophobic molecule. 2. Ammonia is poisonous. 3. Ammonia is a liquid at temperatures which cause chemical reactions to proceed very slowly. 4. Ammonia isn't hydrophobic but also can't form hydrogen bonds between ammonia molecules or to other molecules. 5. Ammonia is a powerful reducing agent. 18) Which of the following contains sulfur covalently bonded to other atoms in its molecular structure? 1. porphyrin 2. cysteine 3. alanine 4. proline 5. cytosine 19) Which of the following is neither an electropositive nor an electronegative atom? 1. Nitrogen 2. Hydrogen 3. Carbon 4. none of the above are correct answers 20) Which of the following is an electronegative atom? 1. Nitrogen 2. Hydrogen http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (4 of 8) [8/29/2000 1:11:49 AM] 3. Carbon 4. none of the above are correct answers 21) Which of the following is most accurate? 1. Lactate is a two carbon molecule. 2. NADPH is produced in glycolysis and used either in the citric acid cycle or in fermentation. 3. Prokaryotes do glycolysis in their mitochondria. 4. none of the above are correct answers 22) Which of the following is an example of a member of the Archea? 1. the spirochete which causes syphilis. 2. Methanococcus jannaschii 3. a mango tree. 4. Giardia 5. More than one of the organisms listed above is a member of the Archea. 23) A few years ago, some scientists proposed that there had been life on Mars because they claimed to have found some evidence in meteorites which are believed to have come from Mars. What sort of evidence was this? 1. cell membranes. 2. stromatolites 3. amino acids 4. complex carbohydrates like those found in the cell walls of modern bacteria. 5. microtubules. 24) Which of the following best describes the Michaels constant, KM? 1. The ratio of the rate constant for formation of ES from E + S to the rate constant for breakdown of ES to E+S. 2. The ratio of the rate constant for formation of ES from E + S to the rate constant for breakdown of ES to E+P. 3. Has units of concentration. 4. Has units of 1/concentration. 5. More than one of the above are equally correct answers. 25) Which of the following are changed when an enzyme is added to catalyze a reaction? 1. The Gibb's energy change for the reaction. 2. The equilibrium constant. 3. The direction of the reaction. 4. The time to reach equilibrium. 26) Professor H. E. Noital claims that "all enzyme catalyzed reactions reach a maximum rate of production of product, no matter how high a substrate concentration." What is the best answer to this claim? 1. It is true because there is usually a relatively small amount of enzyme relative to substrate. 2. It is true because the Gibbs' energy is constant, regardless of substrate concentration, and thus sets a limit on the rate of production of product. 3. It is not true. As substrate concentration increases, the rate of production of product increases more gradually after a certain point but never stops increasing. 4. It is not true. A Lineweaver-Burke plot shows that the rate of production of product increases linearly with respect to the reciprocal of substrate concentration. 27) Which of the following is an enzyme, catalyzing the change of a substrate or substrates to a distinctly different product or products? 1. keratin 2. myosin. 3. myoglobin 4. collagen. 5. silk 28) The alpha helix and beta sheet are found in many different proteins because they are formed by: 1. hydrogen bonding between the amino acid side chains most commonly found in proteins. 2. noncovalent interactions between amino acid side chains and the polypeptide backbone. 3. ionic interactions between charged amino acid side chains. 4. hydrogen bonding between atoms of the polypeptide backbone. 29) Which of the following is true? 1. Peptide bonds are the only covalent bonds that can link together two amino acids in proteins. 2. The polypeptide backbone of some proteins is branched. 3. Nonpolar amino acids tend to be found in the interior of proteins 4. The sequence of the atoms in the polypeptide backbone varies between different proteins. 5. A protein chain ends in a free amino group at the C-terminus. 30) In anaerobic conditions, skeletal muscle produces: 1. lactate and carbon dioxide. 2. ethanol and carbon dioxide 3. lactate only 4. ethanol only 5. ethanol, lactate, and carbon dioxide. 31) The oxidation of sugars by glycolysis to produce pyruvate: 1. occurs only in aerobic organisms. 2. generates carbon dioxide. http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (6 of 8) [8/29/2000 1:11:49 AM] 3. produces a net gain of ATP.. 4. occurs in mitochondria. 5. uses NADH as a source of energy. 32) With respect to standard Gibbs' energy changes, the conversion of NADH to NAD+: 1. is an oxidation which releases about 21.9 kcal/mol. 2. is an oxidation which requires about 21.9 kcal/mol. 3. is a reduction which requires about 14.6 kcal/mol. 4. is an oxidation which releases about 14.6 kcal/mol. 5. is an reduction which releases about 14.6 kcal/mol. 33) Which of the following is a negatively cooperative allosteric enzyme? 1. carbonic anhydrase. 2. hemoglobin. 3. glucokinase 4. 6-phosphofructokinase. 5. None of the above are negatively cooperative allosteric enzymes. 34) Which of the following is most accurate with respect to the addition of glucose units to a growing glycogen chain? 1. Glucose-6-phosphate and GTP form GDPG which then adds a glucose unit to glycogen. 2. Glucose-1-phosphate and GTP form GDPG which then adds a glucose unit to glycogen. 3. Glucose-6-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 4. Glucose-1-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 5. Glucose-3-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 35) The following are lists of phosphorylated activated carrier molecules. Choose the list which best represents a descending rank order of standard Gibbs' energies released when the phosphate group is removed from the carrier. (Choose the list with the highest energy released on the left, the next highest in the central position, and the lowest energy released on the right.) 1. ATP, creatine phosphate, phosphoenolpyruvate. 2. phosphoenolpyruvate, glucose-6 phosphate, creatine phosphate,. 3. creatine phosphate, phosphoenolpyruvate, glucose-6 phosphate,. 4. phosphoenolpyruvate, creatine phosphate, glucose-6 phosphate. 5. ATP, glucose-6 phosphate, phosphoenolpyruvate. 36) Compare the energy of an ionic bond in water to that of a hydrogen bond or a covalent bond. 1. The ionic bond in water has an energy about the same as that of a covalent bond, but very different than that of a hydrogen bond. 2. The ionic bond in water has an energy about the same as that of a hydrogen bond, but very different than that of a covalent bond. http://fig.cox.miami.edu/cgi-bin/tiegen?/usr/ns-home/docs/Faculty/Tom/Exams/255f98e1f1.tie (7 of 8) [8/29/2000 1:11:49 AM] 3. The ionic bond in water is much weaker than a hydrogen bond. 4. Ionic bonds in water are about the same strength as both hydrogen bonds and covalent bonds. 37) Which of the following best describes evidence for the "endosymbiont hypothesis"? 1. Mitochondria and chloroplasts have circular DNA. 2. Archea and eukaryotes share similar gene sequences for some key enzymes. 3. Mycoplasms have a primitive mitochondria-like structure called a mesosome. 4. Stromatolites are found inside the cells of both photosynthetic prokaryotes and some eukaryotes. 38) Which of the following best describes dynein? 1. An enzyme which dephosphorylates ATP. 2. A helical protein found in connective tissue and tendons. 3. The major component of stromatolites. 4. A photosensitive purple pigment found in some photosynthetic bacteria. 39) Which of the following are allosteric activators for the enzyme which phosphorylates fructose 6-phosphate to produce Fructose 1,6-biphosphate? 1. ATP but not citrate or AMP 2. citrate and ATP but not AMP 3. AMP but not citrate or ADP 4. AMP and ADP but not citrate. 40) A protein is characterized by X-ray diffraction as being comprised of a helical structure with 3.3 amino acids per helical turn. The sample of protein was taken from human tendon (ouch!). What is the protein? 1. collagen 2. keratin 3. myoglobin 4. silk Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester - Second Examination - October 29, 1998 Form 1 1) You are reading a biochemical publication which describes the movement of a new drug through cell membranes, Positive values for influx of this drug are plotted against the difference: (concentration of the drug inside the cell minus the concentration outside the cell). As this concentration difference rises from zero to positive values, the influx increases rapidly but then levels off at high values for the concentration difference. Which of the following is the most likely mechanism for movement of the drug across the membrane? 1. simple thermal diffusion. 2. facilitated diffusion 3. active transport. 2) True or False: Lateral (side to side) movement of membrane lipids is characterized by a viscosity approximately equal to that of olive oil. 1. True. 2. False. 3) Which of the following is the type of molecule found on red blood cell membranes and which specifies the ABO blood groups? 1. glycophorin 2. glycocalyx 3. phospholipid 4. cholesterol 5. glycolipid 4) Which of the following best describes the movement of glucose from INSIDE the cells of the intestinal epithelium across the external cell membrane and into the blood plasma? 1. facilitated diffusion cotransport with sodium. 2. facilitated or simple diffusion without cotransport. 3. facilitated diffusion cotransport with potassium. 4. active transport 5) Which of the following methods of microscopy or structure determination can be used to determine the details smaller than the wavelength of the waves used with that particular technique, whether they be electrons (considered as waves), X-rays, or light? 1. electron microscopy. 2. confocal laser scanning microscopy. 3. near field scanning optical microscopy. 4. X-ray diffraction. 5. All of the above are limited to resolve details larger than approximately a quarter wavelength. 6) Which of the following methods of microscopy or structure determination uses a system of pinholes to isolate an image of a very narrow plane of depth in the object being observed? 1. electron microscopy. 2. confocal laser scanning microscopy. 3. near field scanning optical microscopy. 4. X-ray diffraction. 7) You determine the sedimentation coefficient of the small ribosomal subunit of bacteria to be 30S and the large subunit to be 50S. What is the likely sedimentation coefficient for the entire ribosome? 1. 70S 2. 90S 3. 80S 8) How does the reducing power in the NADH produced by glycolysis get into the mitochondria? 1. through the malate-aspartate shuttle. 2. through the creatine-citrate shuttle. 3. by direct diffusion of NADH across both mitochondrial membranes. 4. by facilitated diffusion cotransport of NADH with H+ ions 9) What does the enzyme "ligase" do? 1. It is involved in the breakdown of long-chain fatty acids derived from lipids. 2. It joins Okazaki fragments. 3. It is a key component in the pyruvate dehydrogenase complex. 4. It finds errors in transcription. 5. Ligase joins the two carbon acetyl fragment to oxaloacetic acid to form citric acid. 10) Suppose that the cell membranes of Martians are highly permeable to phosphate (-2) but to no other ions. If the concentration of phosphate inside the cell is 1000mM and the concentration of phosphate outside the cell is 10mM, what is the membrane potential (inside the cell) at 37 degrees C? 1. -124mV. 2. +124mV 3. -62mV 4. +62mV 5. +248mV 11) During protein synthesis, individual amino acids are added at which end of the growing protein chain? 1. always at the carboxyl end. 2. always at the amino end end. 3. At the carboxyl end if the primary transcript was made from one of the DNA strands and at the amino end if the primary transcript was made from the other DNA strand. 12) Which of the following is most accurate with respect to current ideas about the the use of RNA or DNA in the first cells? 1. DNA was the genetic material. 2. RNA was the genetic material. 13) Which of the following best describes ion concentrations inside and outside human cells? 1. Potassium 10mM outside and Sodium 100mM outside. 2. Potassium 100mM outside and Chloride 10mM outside. 3. Chloride 100mM outside and Sodium 10mM outside. 4. Potassium 100mM outside and Sodium 100mM outside. 5. Potassium 100mM outside and Sodium 100mM inside. 14) Which of the following most closely represents the Sodium Nernst potential for human cells at 37 degrees C? (Potentials are always measured inside cells.) 1. -62mV 2. +62mV. 3. +31mV. 4. -31mV. 5. zero 15) The "positive" afterpotential on nerve cell membranes is primarily the result of: 1. decreasing Sodium conductance. 2. increasing Chloride conductance. 3. decreasing Chloride conductance. 4. increasing Potassium conductance. 5. decreasing Potassium conductance. 16) At rest, when there is no action potential, what is the ratio of Sodium conductance to Potassium conductance across a nerve cell membrane? 1. 0.01. 2. 1. 3. 100. 17) During a single action potential, which of the following is most accurate with respect to movement of ions and changes in ion concentration? 1. Enough Sodium enters a nerve cell so that Sodium concentrations rise to 100mM or more. 2. Potassium concentrations inside the cell rise to 100mM or more. 3. Sodium and Potassium concentrations change very little within nerve cells over the course of a single action potential. 18) Identify the molecule phosphatidylcholine. 1. 2. a neurotransmitter substance released by nerve terminals. an important molecule involved in oxidations and reductions in the pyruvate dehydrogenase complex. 3. a type of cholesterol 4. can be bought in some health food stores as "lecithin" 5. used as a primer in DNA synthesis 19) Identify the molecule acetylcholine. 1. 2. a neurotransmitter substance released by nerve terminals. an important molecule involved in oxidations and reductions in the pyruvate dehydrogenase complex. 3. a type of cholesterol 4. can be bought in some health food stores as "lecithin" 5. used as a primer in DNA synthesis 20) Which of the following best describes a "snurp"? 1. a protein particle which splices together RNA. 2. A snurp is the primer for DNA replication. 3. removes pieces of DNA in eukaryotes, producing the final DNA sequence which is then copied onto messenger RNA. 4. a small lipid which fits in between the phospholipids in cell membranes. 21) With respect to the terms "saturated fat" and "unsaturated fat", which of the following is most accurate? 1. Saturated fats have very little cholesterol. 2. Saturated fats have a large amount of cholesterol. 3. Saturated fats have lots of double bonds in the fatty acid chains. 4. Saturated fats have few or no double bonds in the fatty acid chains. 5. Two of the above answers are equally correct. 22) In human cells, where is carbon dioxide made and how many are made per single glucose molecule metabolized, from pyruvate through the citric acid cycle? 1. One molecules are made in the citric acid cycle and two in the pyruvate dehydrogenase complex. 2. Two molecules are made in the citric acid cycle and one in the pyruvate dehydrogenase complex. 3. Four molecules are made in the citric acid cycle and two in the pyruvate dehydrogenase complex. 4. Two molecules are made in the citric acid cycle and four in the pyruvate dehydrogenase complex. 5. No carbon dioxide is made or released in either of these processes. 23) In human cells, where is GTP made and how many are made per single glucose molecule metabolized, from pyruvate through the citric acid cycle? 1. two molecules in the pyruvate dehydrogenase complex. 2. two molecules in the citric acid cycle 3. one molecule in the pyruvate dehydrogenase complex. 4. one molecule in the citric acid cycle 5. No GTP is made or released in either of these processes. 24) Which of the following best describes an exon? 1. Non-coding sequences of DNA, found in both animals and prokaryotes. 2. Coding sequences of DNA, found in both animals and prokaryotes. 3. Non-coding sequences of DNA, not found in prokaryotes. 4. Coding sequences of DNA, not found in prokaryotes. 25) During DNA replication, individual nucleotide bases are added at which end of the new, growing DNA strand? 1. always at the 5' end. 2. always at the 3' end. 3. At the 3' end on the leading strand and at the 5' end on the lagging strand. 4. At the 5' end on the leading strand and at the 3' end on the lagging strand. 26) In the pyruvate dehydrogenase complex: 1. NADH is produced by direct reduction by a reduced lipoamide side chain. 2. NADPH is produced by direct reduction by thiamine pyrophosphate. 3. NAD+ is produced by direct reduction by thiamine pyrophosphate. 4. NADPH is produced by direct reduction by pyruvate. 5. no NADH or NADPH is produced by this enzyme complex. 27) Suppose you are measuring sedimentation coefficients of some particles. If you double the rotational speed of the rotor (rpm - rotations per minute), what happens to the centrifugal acceleration? 1. It doubles. 2. It stays the same. 3. It decreases to half. 4. It quadruples. 5. It decreases to one-quarter. 28) Suppose you are measuring sedimentation coefficients of some particles. If you double the rotational speed of the rotor (rpm - rotations per minute), what happens to the sedimentation coefficient? 1. It doubles. 2. It stays the same. 3. It decreases to half. 4. It quadruples. 5. It decreases to one-quarter. 29) What is the function of the SDS in SDS-PAGE? 1. Denatures protein. 2. Helps excise a piece from a strand of RNA. 3. SDS is a fluorescent dye which helps make the bands on the gel visible. 4. The SDS is a photoelectric sensor which detects light and outputs a signal to a computer. 30) The sodium driven symport in animal cells is replaced by what in plant cells? 1. Plant cells use a sodium driven symport just as in animal cells. 2. a potassium ion driven symport. 3. a magnesium ion driven symport. 4. a hydrogen ion driven symport. 5. Plant cells require both sodium and potassium to be cotransported with solute. 31) Which of the following methods uses a fiber-optic waveguide to illuminate a specimen? 1. snRNP. 2. near field scanning optical microscopy. 3. confocal laser scanning microscopy. 4. SDS-PAGE. 5. PAL optical systems. 32) In humans, which of the following contains an unusual type of cell called a "hair cell"? 1. The retina. 2. muscle. 3. the cochlea. 4. the intestinal epithelium. 33) Suppose that the membrane potential was governed by a single, highly permeable ion. Now, suppose that we could instantly double the charge on all ions of that type. What would happen to the membrane potential? 1. It would stay the same. 2. It would double. 3. It would decrease to half. 4. It would increase but not to double. 5. It would decrease but not to half. 34) Which of the following best describes the action of the Na+/K+ pump? 1. For each ATP used, 3 sodium ions are pumped out from the cell and 2 potassium ions are pumped into the cell. 2. For each ATP used, 2 sodium ions are pumped out from the cell and 3 potassium ions are pumped into the cell. 3. For each ATP used, 1 sodium ion is pumped out from the cell and 1 potassium ion is pumped into the cell. 4. For each ATP used, 3 sodium ions are pumped into the cell and 2 potassium ions are pumped out from the cell. 5. For each ATP used, 2 sodium ions are pumped into the cell and 3 potassium ions are pumped out from the cell. 35) Suppose that the membrane potential was governed by a single, highly permeable ion with charge +1. Now, suppose that we could instantly increase the concentration of that ion outside the cell to 10 times its original value. What would happen to the membrane potential, assuming that the temperature stayed at a constant 37 degrees C? 1. It would stay the same. 2. It would increase to 10 times its original value. 3. It would decrease to 1/10 its original value. 4. It would increase to its original value plus 62mV. 5. It would decrease to its original value minus 62mV. 36) Suppose that the membrane potential was governed by a single, highly permeable ion with charge +1. Now, suppose that we could instantly increase the concentration of that ion inside the cell to 10 times its original value. What would happen to the membrane potential, assuming that the temperature stayed at a constant 37 degrees C? 1. It would stay the same. 2. It would increase to 10 times its original value. 3. It would decrease to 1/10 its original value. 4. It would increase to its original value plus 62mV. 5. It would decrease to its original value minus 62mV. 37) At the peak of the action potential, which of the following best describes the order of membrane permeabilities? 1. potassium (greatest), sodium (less), chloride (least). 2. sodium (greatest), chloride (less), potassium (least). 3. potassium (greatest), chloride (less), sodium (least). 4. sodium (greatest), potassium (less), chloride (least). 5. chloride (greatest), sodium (less), potassium (least). 38) While doing some research on a newly discovered marine invertebrate, you find that its cells are only permeable to one type of ion. But you do not know what ion it is. You determine that the concentration of this ion inside the cells is 10 mM and the concentration outside the cells is 0.1 mM. The membrane potential is -62 mV at 37 degrees C. Which of the following is most likely the ion in question? 1. Iron (+3) 2. Potassium (+1) 3. Calcium (+2) 4. Phosphate (-2) 5. Chloride (-1) 39) With which of the following would you most likely find 3'- 5' exonuclease activity associated? (This question has no correct answer - Everyone was given credit when this exam was scored.) 1. joining of Okazaki fragments. 2. formation of peptide bonds during protein synthesis. 3. the pyruvate dehydrogenase complex. 4. facilitated diffusion co-transport 5. error correction during transcription. 40) Suppose we just had the normal concentrations of organic anions and chloride inside and outside a cell but no sodium or potassium either inside or outside the cell. What would most likely happen? 1. The cell would shrink due to water leaving. 2. The cell would expand due to water entering. 3. The cell would still be in osmotic balance and would neither shrink or expand. Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester - Third Examination - 24 November, 1998 Form 1 1) Which of the following prevents polymerization of actin to form microfilaments? 1. colchicine. 2. rotenone 3. silica 4. taxol. 5. cytochalasin B. 2) Thin filaments of human skeletal muscle consist primarily of: 1. myosin. 2. alpha-actinin. 3. dynein. 4. tubulin. 5. actin. 3) What is Ras? 1. A growth hormone which causes release of cyclic AMP into the cytoplasm of rat cells. 2. Prevents transfer of electrons to water in mitochondria. 3. A protein which is activated by receptor tyrosine kinases. 4. A human hormone which causes intracellular release of intracellular inositol 1,4,5-trisphosphate. 5. It acts in a very similar way to CN-. 4) Which of the following structures is adjacent to or most closely associated with T-tubules? 1. mitochondrial inner membrane 2. thylakoid membranes 3. Golgi apparatus. 4. lysosomes. 5. sarcoplasmic reticulum. 5) What is vasopressin? 1. A growth hormone which causes release of cyclic AMP into the cytoplasm of rat cells. 2. Prevents transfer of electrons to water in mitochondria. 3. A protein which is activated by receptor tyrosine kinases. 4. A human hormone which causes intracellular release of inositol 1,4,5-trisphosphate. 5. It acts in a very similar way to CN-. 6) True or False: "C4 photosynthesis does not replace the C3 Calvin-Benson cycle with a new cycle involving four carbon molecules. C4 plants have the C3 Calvin-Benson cycle." 1. True. 2. False. 7) With which of the following would you expect to find "clathrin" associated? 1. ATP synthase in mitochondria. 2. light-dependent reactions of photosynthesis. 3. movement of vesicles within cells. 4. thin filaments of skeletal muscle. 5. eukaryotic flagella. 8) Which of the following prevents disassembly of microtubules into tubulin subunits? 1. colchicine. 2. rotenone 3. silica 4. taxol. 5. cytochalasin B. 9) A mitochondrion is surrounded by folds of endoplasmic reticulum to form a ________ prior to breakdown and recycling of its components. 1. thylakoid. 2. autophagosome. 3. sarcomere. 4. Ras. 5. peroxisome. 10) Which of the following is an internal cell messenger which stays imbedded in the external cell membrane and is not released into the cytosol? 1. cAMP 2. calcium 3. inositol 1,4,5-trisphosphate 4. diacylglycerol 5. adrenaline 11) In a mitochondrion, the energy supplied by a single FADH2 to the electron transport chain results in transfer of how many hydrogen ions from the matrix to the intermembrane space? 1. 0 2. 1 3. 2 4. 3 5. 4 12) Suppose that hydrogen ion concentrations are higher in the interior of the mitochondrion than they are in the space between the inner and outer mitochondrial membranes. Which of the following is most likely? 1. ATP will be made by the ATP synthase. 2. ATP will be used by the ATP synthase. 3. ATP is neither made or used by the ATP synthase. 13) True or False: "Prokaryotic cilia and flagella are powered by ATP hydrolysis by dynein." 1. True. 2. False 14) What is rotenone? 1. A growth hormone which causes release of cyclic AMP into the cytoplasm of rat cells. 2. Prevents transfer of electrons to water in mitochondria. 3. A protein which is activated by receptor tyrosine kinases. 4. A human hormone which causes intracellular release of intracellular inositol 1,4,5-trisphosphate. 5. It acts to block a portion of the electron transport chain. 15) When adrenaline is released into the bloodstream and subsequently binds to receptor proteins on human liver cells, which of the following is most likely? 1. phospholipase C is activated inside the liver cells. 2. cAMP concentrations go down inside the liver cells. 3. The rate at which glucose units are added to glycogen decreases. 4. In the mitochondria, rotenone is made from citric acid more rapidly than normal. 16) What is the typical concentration of calcium inside cells at rest, assuming that it is not being released into the cytosol from some intracellular compartment? 1. 1/100 Molar. 2. 1/10,000 Molar. 3. 1/10,000,000 Molar. 4. 1/1,000,000,000 Molar. 17) Which of the following is a contractile protein which carries cargo molecules towards the outside of cells on microtubules? 1. actin 2. myosin 3. dynein 4. kinesin. 18) What is the effect of increased GTP concentrations on microtubules? 1. microtubules grow. 2. microtubules depolymerize and shrink 3. GTP has no effect. Only ATP has an effect. 19) Which of the following best describes the function of the Lohmann reactions? 1. 2. 3. Stores carbon dioxide as part of four carbon molecules in some plants. Makes ATP using the concentration gradient of hydrogen ions across the inner mitochondrial membrane. Buffers ATP concentrations in the interior of the myofibril. 4. One of the light dependent reactions of photosynthesis. 20) What, if anything, does the molecule nitroglycerin have to do with human biology? 1. Nitroglycerin dissolved in water makes NO2, nitrous oxide, which dentists use as an anesthetic. 2. Nothing other than Nobel who initiated the Nobel prizes made his fortune from nitroglycerin. 3. Nitroglycerin breaks down to form a common signal molecule, which can enter smooth muscle cells. 4. Nitroglycerin is the backbone of many glycerol-based membrane lipids involved in cell communication. 21) Which of the following extracellular signals DO NOT involve a G-protein? 1. Signal molecules which activate receptor tyrosine kinases. 2. Glucagon doesn't involve a G-protein but adrenaline does. 3. Glucagon doesn't involve a G-protein but thrombin does. 4. Neither glucagon nor adrenaline involves the use of a G-protein. 5. Light absorbed by receptor cells in the retina. 22) About how long was the interval between the evolution of the first organisms which could split water and produce oxygen gas and the time at which aerobic respiration became widespread? 1. about 1 billion years. 2. about 1 million years. 3. less than 10,000 years. 4. more than 10 billion years. 23) What is ubiquinone or what process is it most closely associated with? 1. It is a hormone. 2. It is an intracellular messenger associated with increased levels of cAMP. 3. It is found imbedded in the mitochondrial inner membrane. 4. It is the light sensitive molecule in human rod and cone cells. 5. It is found only in chloroplasts and not in mitochondria. 24) You are a very clever researcher and find an artifical electron acceptor for electrons coming from the cytochrome b-c1 complex in the electron transport chain of mitochondria. Simultaneously, you block electron transfer to the cytochrome oxidase complex. Now, you let the electron transport run with a normal supply of reduced NADH as electron donors. (Assume that there is no FADH2.) What is likely to happen? 1. ATP production will drop to 1/3 of normal and water production will drop to zero. 2. ATP production will drop to 2/3 of normal and water production will drop to zero. 3. ATP production will drop to 1/3 of normal and water production will remain at normal levels. 4. ATP production will drop to 2/3 of normal and water production will remain at normal levels. 5. ATP production will drop to zero and water production will remain at normal levels. 25) How much standard free (Gibbs) energy is lost by electrons from the time they enter the electron transport chain of mitochondria to the end of the electron transfer process? (The answer to this question was mean to be 25 kcal./mole, which represents the energy drop through the entire electron transport chain. However, one could be confused if FADH2 is considered. So, credit was given for any answer to this question.) 1. 15 kcal/Mole. 2. 7 kcal/Mole. 3. 1200 kcal/Mole. 4. 25 kcal/Mole. 5. 800 kcal/Mole. 26) Which of the following most accurately characterizes a Z-disk? 1. One of the flattened, membrane bounded disks of the Golgi apparatus. 2. The interior is comprised mostly of the protein alpha-actinin. 3. It is found in the middle of the sarcomere in vertebrates and connects together the thick filaments. 4. A Z disk is one of the flattened disks in the rod cells of the vertebrate retina. 27) Which of the following prevents polymerization of tubulin to form microtubules? 1. colchicine. 2. rotenone 3. silica 4. taxol. 5. cytochalasin B. 28) Which of the following is the calcium binding protein in human skeletal muscle? 1. actin 2. troponin 3. alpha-actinin 4. tropomyosin 5. dynein 29) Which of the following is most closely associated with "photorespiration"? 1. Lohman reaction. 2. light dependent reactions of photosynthesis. 3. Oxygen gas is a substrate for Ribulose-1-5-bisphosphate carboxylase. 4. lysosomes. 30) Detoxification of barbituates is thought to take place in the: 1. smooth endoplasmic reticulum. 2. rough endoplasmic reticulum. 3. bundle sheath cells. 4. mitochondria. 5. lysosomes. 31) Chlorophyll absorbs which of the following wavelengths of light? 1. green but not red or blue. 2. green and red but not blue. 3. red but not blue or green. 4. blue and green but not red. 5. blue and red but not green. 32) Cyclic photophosphorylation generates which of the following? 1. ATP but no NADPH or oxygen gas. 2. oxygen gas, NADPH, and ATP. 3. NADPH and ATP but no oxygen gas. 4. NADPH but no ATP or oxygen gas. 33) True or False: "Both photosystem I and photosystem II split water to produce oxygen gas." 1. True 2. False 34) A biochemist is describing a process by saying: "In the mesophyll cells, the carbon dioxide combines with phosphoenolpyruvate to form a 4 carbon molecule. This molecule is converted to ________, which then moves into the bundle sheath cells.". Fill in the blank. 1. oxaloacetic acid. 2. citric acid. 3. malic acid. 4. diacylglycerol 35) Kranz anatomy is associated with: 1. skeletal muscle structure. 2. leaves of some plants which live in hot climates. 3. large amounts of Golgi. 4. the structure of cristae. 36) You are talking to a cell biologist who has discovered a new intracellular structure. She calls it a "sarcoplop". What kind of cell do you think she is working on? 1. a vertebrate muscle cell. 2. a bundle sheath cell. 3. a liver cell. 4. a sperm cell. 37) With which of the following would you expect to find "a 9+2 structure" associated? 1. ATP synthase in mitochondria. 2. light-dependent reactions of photosynthesis. 3. movement of vesicles within cells. 4. thin filaments of skeletal muscle. 5. eukaryotic flagella. 38) What is the carbohydrate which is produced by the Calvin-Benson cycle and the major product which goes on to make other sugars, fatty acids, and amino acids? 1. 1,3-diphosphoglycerate 2. ribose 3. mannose 4. glyceraldehyde-3-phosphate. 5. phosphoenolpyruvate 39) Which of the following best describes a myofibril? 1. a doublet microtubule found in flagella 2. can be applied to either a single thin or thick filament in skeletal striated muscle. 3. a bundle of thick and thin filaments surrounded by Golgi. 4. Myofibrils are separated by sarcoplasmic reticulum, inside of which Calcium is stored. 40) What conditions in skeletal, striated muscle directly result in rigor? 1. low calcium concentrations in the region of the thick and thin filaments. 2. low ATP concentrations in the region of the thick and thin filaments. 3. continuous stimulation by the nerve 4. too much creative phosphate poisons the muscle. Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester, 1998 - Final Exam Form 1 1) A particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics. You make a plot of Vmax/V vs. 1/[S]. You draw a straight line which best fits this data and determine that the intercept of this line with the Vmax/V axis is 2.0 and the intercept with the 1/[S] axis is -2.5mM-1. Which of the following is most likely true? 1. Competitive inhibition must be taking place. 2. Noncompetitive inhibition must be taking place. 3. Either no inhibition or competitive inhibition must be taking place but can't tell which from the data given. 4. Either no inhibition or noncompetitive inhibition must be taking place but can't tell which from the data given. 5. Some kind of inhibition must be taking place but can't tell which from the data given. 2) Which of the following organisms has two haploid nuclei? 1. The bacterium which causes the most common form of Typhus. 2. Stromatolites. 3. a mycoplasm. 4. Giardia 3) True or False: Solid ammonia floats in liquid ammonia just like water ice floats in liquid water. 1. True 2. False 4) The Lohman reaction is found in which of the following? 1. skeletal muscle cells 2. lysosomes 3. Golgi apparatus 4. CD8 cells 5. bundle sheath cells 5) Which of the following is most accurate with respect to the addition of glucose units to a growing glycogen chain? 1. Glucose-6-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 2. Glucose-1-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 3. Glucose-6-phosphate and GTP form GDPG which then adds a glucose unit to glycogen. 4. Glucose-1-phosphate and GTP form GDPG which then adds a glucose unit to glycogen. 5. Glucose-3-phosphate and UTP form UDPG which then adds a glucose unit to glycogen. 6) A protein is characterized by X-ray diffraction as being comprised of a helical structure with 3.6 amino acids per helical turn. The sample of protein was obtained by cleaning up the hair left on the floor by Dr. Herbert's cats. What is the protein? 1. collagen 2. keratin 3. myoglobin 4. silk 7) A colleague tells you that a particular enzyme catalyzed reaction obeys Michaelis-Menten kinetics and that at a substrate concentration of 3mM, the reaction velocity is one-quarter of maximum. What is the Michaelis constant, KM? 1. 9.0 mM 2. 0.75 mM 3. 1.0 mM 4. 4.0 mM 5. 3.0 mM 8) Which of the following is closest to the ratio of Potassium conductance to Sodium conductance (PK/PNa) across a typical resting muscle cell membrane at the peak of the action potential? 1. 1000.00 2. 0.1 3. 1.00 4. 10.00 5. 100.00 9) A typical value for the Chloride Nernst potential of a typical human nerve cell is: 1. +60mv 2. -60mv 3. -200mv 4. zero 5. +200mv. 10) Which of the following is the immunoglobulin most closely associated with allergy/hypersensitivity reactions ? 1. IgA 2. IgE 3. IgG 4. IgM 11) Which of the following is the immunoglobulin with the highest molecular weight? 1. IgA 2. IgE 3. IgG 4. IgM 12) Which of the following is the most significant immunoglobulin associated with the defense of mucous membranes of the nose, mouth and throat? 1. IgA 2. IgE 3. IgG 4. IgM 13) Suppose that cell membranes of a particular cell are permeable only to iron (Fe+3). If external iron concentration, (Fe+3)out = 0.001 mM and internal iron concentration, (Fe+3)in = 1.0 mM, what is the membrane potential, V, inside the cell (at 37 degrees C)? 1. -62mV 2. -248mV 3. +83mV. 4. -83mV 5. +248mV 14) Suppose that calcium (Ca+2) is the only ion to which the cell membrane is freely permeable. The concentration of calcium inside the cell is 10 mM. If the membrane potential inside the cell is 0 mV (at 37 degrees C), what is the concentration of calcium outside the cell? 1. 1 mM 2. 10 mM 3. 100 mM 4. 0.10mM 5. 0.01mM 15) Kranz anatomy is usually associated with plants which 1. 2. live in very cool, moist places have a curious reaction scheme which stores carbon dioxide by combining it with ribulose-1,5, bisphosphate to form 3-phosphoglycerate. 3. have a developed mesophyll which closely surrounds the bundle sheath cells. 4. have only the Calvin-Benson cycle. 5. have strangely developed mitochondria 16) Your roommate has just swallowed a quantity of antifreeze solution containing almost 100% ethylene glycol. No physician is available and you wish to save that person's life - What should you do? 1. Administer oxalic acid to your roommate. 2. Administer methanol to your roommate. 3. Administer more ethylene glycol to your roommate. 4. Administer glycerol to your roommate. 5. Administer ethanol to your roommate. 17) Which of the following is a realistic structure for an amino acid side chain and would be most likely to participate in hydrophobic bonding between different regions of a protein chain? 1. -CH2-CH2-C00- 2. -(CH2)4-NH2 3. -CH2-SH 4. -CH2-CH2-PO4 5. -CH2-CH2-CH3 18) With respect to the Golgi apparatus: 1. It is a microfilament based contractile organelle in wood roaches. 2. It contains many destructive enzymes and primarily attacks endocytosed materials. 3. It is responsible for the conversion of proinsulin to insulin. 4. Found only in plants with Kranz anatomy. 5. Stores calcium in striated muscle cells. 19) Where would you most likely find Lysozyme? 1. In lysosomes. 2. In bundle sheath cells. 3. In stromatolites. 4. In the mucous of the human mouth or nose. 5. In the M-line of a human sarcomere. 20) Which of the following is true with respect to a plot of reaction velocity V vs. substrate concentration S for an allosteric enzyme? 1. The shape of the plotted function looks very similar to the plot of percent saturation vs. partial pressure of oxygen for hemoglobin. 2. In the presence or absence of an inhibitor, as S increases, the velocity always must approach the same value for Vmax. 3. Allosteric enzymes consist of only a single, continuous protein chain. 4. Allosteric enzymes are any enzymes which don't obey Michaelis-Menten kinetics 21) Which of the following is a protein structure which has all main chain C=O and N-H hydrogen bonded to each other within a single protein chain? 1. beta pleated sheet 2. collagen helix 3. alpha helix 22) Suppose that we are studying an enzyme catalyzed reaction for which the product, once released, can bind to the enzyme and be converted back to substrate. Which of the following is most accurate with respect to this reaction? 1. Most biochemical reactions go backwards in just this way. 2. The situation proposed in this question violates the steady state assumption of Michaelis-Menten kinetics. 3. The situation proposed in this question violates the assumption of Michaelis-Menten kinetics that product does not bind to the enzyme. 4. Myosin follows the situation proposed - Myosin will bind ADP to make ATP if there is enough Creatine phosphate 23) Which of the following is most accurate concerning the entropy of ATP, ADP, and inorganic phosphate? 1. The sum of the entropies of ADP and phosphate is greater than the entropy of ATP. 2. The the entropy of ATP is greater than the sum of the entropies of ADP and phosphate. 3. The sum of the entropies of ADP and phosphate is equal to the entropy of ATP. 24) Which of the following best describes the movement of glucose from the lumen of the intestine across the membrane of the cells of the intestinal epithelium? 1. facilitated diffusion cotransport with sodium. 2. facilitated or simple diffusion without cotransport. 3. facilitated diffusion cotransport with potassium. 4. active transport 25) Which of the following is a major component in removing introns and splicing together two exons? 1. lysozyme. 2. Ras 3. Golgi apparatus 4. snRNP 5. Inositol 26) Which of the following methods of microscopy or structure determination uses can resolve structures which are smaller than the diffraction limit for the wavelength of radiation used? 1. near field scanning optical microscopy. 2. X-ray diffraction. 3. electron microscopy. 4. confocal laser scanning microscopy. 27) The process of removing introns and splicing together exons occurs in which of the following ways: 1. 2. The double stranded DNA in the chromosome is cut and rejoined. A region of DNA is transcribed into RNA. It is this piece of RNA that is cut and spliced together. 3. A continuous protein chain is made from the information contained in mRNA. It is this protein chain that is cut and spliced together. 4. A region of the chromosome is copied onto a single strand of DNA. It is this piece of DNA that is cut and spliced together. 5. Inositol 28) The "positive" afterpotential on nerve cell membranes occurs partially as a result of: 1. Potassium and Chloride Nernst potentials aren't exactly equal for most nerve cells. 2. The afterpotential is approximately equal to the Sodium Nernst potential. 3. The afterpotential is approximately equal to the Chloride Nernst potential. 29) You are reading a biochemical publication which describes the movement of a new drug through cell membranes, Positive values for efflux of this drug are plotted against the difference: (concentration of the drug inside the cell minus the concentration outside the cell). As this concentration difference rises from zero to positive values, the efflux increases linearly without leveling off. Which of the following is the most likely mechanism for movement of the drug across the membrane? 1. simple thermal diffusion. 2. facilitated diffusion 3. active transport. 30) Which of the following is a member of the Archea? 1. stromatolites 2. mycoplasms 3. Giardia 4. Methanococcus 5. Chlamydia 31) Which of the following is an organism or group of organisms which includes the smallest living cells? 1. stromatolites 2. mycoplasms 3. Giardia 4. Methanococcus 5. Chlamydia 32) Lethal yellowing, a disease which affects coconut palms, is cause by which of the following? 1. stromatolites 2. mycoplasms 3. Giardia 4. Methanococcus 5. Chlamydia 33) Where would you most likely find doublet microtubules, which look like two microtubules fused together side-to-side, sharing a common wall? 1. prokaryotic cilia and flagella 2. the contractile ring which is responsible for cytokinesis 3. the thick filaments of muscle 4. the thin filaments of muscle 5. eukaryotic cilia and flagella 34) Which of the following best describes photorespiration? 1. Uses oxygen but requires ATP instead of making it. 2. Occurs in the mitochondrial matrix. 3. Occurs in the mitochondrial inner membrane. 4. Part of the light dependent reactions of photosystems I and II. 5. Occurs only in the autophagosomes. 35) If a solution of 1000 hemoglobin molecules is 50% saturated with oxygen, on the average, how many oxygen molecules are bound to hemoglobin in this solution? 1. 4000 2. 250 3. 500 4. 125 5. 2000 36) If a solution of 1000 myoglobin molecules is 50% saturated with oxygen, on the average, how many oxygen molecules are bound to myoglobin in this solution? 1. 4000 2. 250 3. 500 4. 125 5. 2000 37) Which of the following is an inhibitor of cytokinesis? 1. glucagon 2. cytochalasins 3. ubiquinone 4. colchicine 5. vasopressin 38) Which of the following is a hormone which increases intracellular production of cyclic AMP? 1. glucagon 2. cytochalasins 3. ubiquinone 4. colchicine 5. vasopressin 39) Which of the following is a hormone which increases intracellular production of diacylglycerol? 1. glucagon 2. cytochalasins 3. ubiquinone 4. colchicine 5. vasopressin 40) Which of the following is most closely associated with a Fab subfragment? 1. Myosin II 2. 9+2 structure 3. hemoglobin 4. B-lymphocyte 5. proinsulin 41) Which of the is an extracellular signal closely associated with a rise in intracellular cyclic GMP? 1. acetylcholine 2. nitric oxide 3. adrenaline 4. nitrous oxide 5. Ras 42) In a leaf which is doing C4 photosynthesis, at which of the following locations is one most likely to find the Calvin-Benson cycle? 1. in the chloroplast membranes of the mesophyll cells. 2. in the cytosol of the mesophyll cells. 3. in the mitochondrial matrix of the bundle sheath cells. 4. in the chloroplast stroma of the bundle sheath cells. 5. in the mitochondrial inner membrane of the mesophyll cells. 43) In a leaf which is doing C4 photosynthesis, at which of the following locations is one most likely to find the addition of Carbon dioxide to PEP to form Oxaloacetate? 1. in the chloroplast membranes of the bundle sheath cells. 2. in the mesophyll cells. 3. in the mitochondrial matrix of the bundle sheath cells. 4. in the chloroplast stroma of the bundle sheath cells. 5. in the mitochondrial inner membrane of the bundle sheath cells. 44) A protein secreted by neighboring cells, that binds to a cell surface receptor, activating a signaling pathway which leads to cell division. (Dr. Handel) 1. survival factor 2. growth factor 3. apoptotic factor 4. p53 45) Which type of gene, if mutated, may be considered a tumor suppressor gene. (Dr. Handel) 1. cyclin dependent kinase (cdk) inhibitor 2. cyclin 3. cyclin dependent kinase 4. oncogene 46) When DNA damage occurs, this cyclin dependent kinases (cdk) inhibitor can bind an S phase cyclin-cdk complex rendering it inactive and leading to a halt in the cell cycle. (Dr. Handel) 1. MPF 2. RAS 3. CDK2 4. p21 47) Which term or phrase can best be described as programmed cell death. (Dr. Handel) 1. apoptosis 2. cell injury 3. cell cycle progression 4. cell division 48) The "overactivation" of ___________ may cause tumors to develop. (Dr. Handel) 1. cyclin dependent kinase (cdk) inhibitors 2. tumor suppressor genes 3. oncogenes 4. apoptotic factors 49) Anfinsen, Moore, and Stein used __________ to break disulfide bonds between side chain groups of amino acids. 1. urea 2. cytochalasins 3. lysozyme 4. colchicine 5. mercaptoethanol 50) The inner surface of red blood cell membranes has transmembrane proteins cross-linked by a network of the protein __________. 1. diacylglycerol 2. spectrin 3. rhodopsin 4. colchicine 5. cephalin 51) Which of the following is a membrane lipid which can be characterized as being saturated or unsaturated? 1. cholesterol 2. kinesin 3. colchicine 4. urea 5. cephalin 52) Glucokinase and __________ both catalyze the same biochemical reaction, except that the two enzymes have different values for KM and are used in different type of cells. 1. ribulose bisphosphate carboxylase 2. phosphofructokinase 3. malate dehydrogenase 4. hexokinase 5. creatine phosphokinase 53) What is thiamine pyrophosphate used for in the pyruvate dehydrogenase complex? 1. Thiamine pyrophosphate holds the acetate fragment of pyruvate temporarily in the step where carbon dioxide is split off. 2. Thiamine pyrophosphate has reduced sulfur groups which become oxidized in the step when NADH is reduced to NAD+. 3. Thiamine pyrophosphate has reduced sulfur groups which become oxidized in the step when NAD+ is reduced to NADH. 4. Thiamine pyrophosphate has oxidized sulfur groups which become reduced when an acetate fragment is transferred to them. 54) In the malate-aspartate shuttle, which of the following is most correct concerning movement of different molecules across the mitochondrial inner membrane? 1. Glutamate and alpha-Ketoglutarate both move into the mitochondrial matrix while Aspartate and Malate both move out. 2. Glutamate and Malate both move into the mitochondrial matrix while Aspartate and alpha-Ketoglutarate both move out. 3. Glutamate and Aspartate both move into the mitochondrial matrix while alpha-Ketoglutarate and Malate both move out. 4. Aspartate and Malate both move into the mitochondrial matrix while Glutamate and alpha-Ketoglutarate both move out. 5. Aspartate and alpha-Ketoglutarate both move into the mitochondrial matrix while Glutamate and Malate both move out. 55) Suppose that you learn that life on a distant planet seems very similar to that on Earth, except that there are no Pyrimidines! What might be the consequence of this difference? 1. The triplet code of Earth would have to become a sequence of six bases to provide the same amount of genetic information. 2. Processes which require reduction of NAD+ wouldn't work since Pyrimidines are required for these processes. 3. Hemoglobin couldn't be used as an Oxygen carrier since Pyrimidine is the component of hemoglobin which binds Iron and Oxygen. 4. There would be no consequence since Pyrimidine is just a laboratory reagent not naturally occuring in cells. 56) What is the location of the terminal phosphate group on a strand of DNA? 1. always at the 3' end. 2. always at the 5' end. 3. At the 3' end on the leading strand and at the 5' end on the lagging strand. 4. At the 5' end on the leading strand and at the 3' end on the lagging strand. 5. A phosphate is found on both the 3' and 5' end. 57) During DNA replication, individual nucleotide bases are added at which end of the new, growing DNA strand? 1. always at the 3' end. 2. always at the 5' end. 3. At the 3' end on the leading strand and at the 5' end on the lagging strand. 4. At the 5' end on the leading strand and at the 3' end on the lagging strand. 58) True or False: Myosin is an allosteric enzyme 1. True. 2. False 59) Which of the following is most accurate concerning ATP hydrolysis by Myosin? 1. ATP is hydrolyzed immediately after Actin and Myosin bind to each other. 2. ATP is hydrolyzed and the products are released immediately before Actin and Myosin bind to each other. 3. ATP is hydrolyzed immediately before Actin and Myosin bind to each other but the products are released after binding. 4. Myosin releases from Actin immediately upon ATP hydrolysis. 60) If you were going to denature proteins, which of the following would you NOT use? 1. SDS. 2. mercaptoethanol 3. urea 4. purine Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester - First Examination - September 24, 1996 Form 1 1) Professor I. M. Hotair makes the statement: "Hydrogen gas was in high concentration in the early Earth's atmosphere". Which of the following would be a most appropriate response to this statement? 1. Hydrogen gas was a major component of the atmosphere but it reacted with methane to form water and some other molecules. 2. Hydrogen gas disappeared from the atmosphere because gravity could not hold a molecule with such low mass. 3. Hydrogen gas was not in high concentration in the very early Earth's atmosphere but rose in concentration and probably was involved in the extinction of dinosaurs. 4. The statement is in error, hydrogen gas was never a major component of the Earth's atmosphere. 5. Hydrogen gas in the early Earth's atmosphere burnt as the result of all the lightning and together with oxygen formed water. 2) Which of the following are prokaryotes which we believe to be most closely related to the first prokaryotes to appear on Earth? 1. members of the Archebacteria. 2. members of the Cyanobacteria. 3. Mycoplasmas. 4. prokaryotes which contain mesosomes. 5. members of the Fabaceae. 3) Approximately, what is the diameter of the smallest cells living today? 1. about 5 times the thickness of a typical cell membrane. 2. about 20 times the thickness of a typical cell membrane. 3. about 50 times the thickness of a typical cell membrane. 4. about 200 times the thickness of a typical cell membrane. 4) Approximately, when did the first cells appear on Earth? 1. 4 x 106 years ago. 2. 4 x 1012 years ago. 3. 4 x 109 years ago. 4. 4 x 1015 years ago. 5) Suppose that heterotrophs appeared on Earth just as we believe they did but autotrophs never existed. What do you suppose might have been the consequence of this change in evolutionary history? 1. No serious consequences except that plants wouldn't have appeared and we would have to settle for rock gardens. 2. Animal life would have appeared except that it would have been unlikely to evolve much past very simple organisms due to the lack of mitochondria. 3. All life on Earth would probably have become extinct, except for perhaps a few primitive bacteria-like organisms in hot pools near volcanos. 6) Which of the following includes the smallest cells presently living on Earth? 1. members of the Archebacteria. 2. members of the Cyanobacteria. 3. Mycoplasmas. 4. prokaryotes which contain mesosomes. 5. members of the Fabaceae. 7) Which of the following are prokaryotic autotrophs which use chlorophyll? 1. members of the Archebacteria. 2. members of the Cyanobacteria. 3. Mycoplasmas. 4. prokaryotes which contain mesosomes. 5. members of the Fabaceae. 8) Assume that you are studying an enzyme catalyzed reaction which obeys Michaelis-Menten kinetics. Suppose that Km = 20 mM. If V = Vmax/2, what is the substrate concentration? 1. 10 mM 2. 18 mM 3. 20 mM 4. 22 mM 5. 40 mM 9) Assume that you are studying an enzyme catalyzed reaction which obeys Michaelis-Menten kinetics. Suppose that Km = 10 mM. If V = Vmax/3, what is the substrate concentration? 1. 2.5 mM 2. 5 mM 3. 10 mM 4. 20 mM 5. 30 mM 10) Which of the following are characteristics of allosteric enzymes? 1. a single subunit and a sigmoid relationship between reaction velocity and substrate concentration. 2. a single subunit and a rectangular hyperbolic relationship between reaction velocity and substrate concentration. 3. multiple subunits and a rectangular hyperbolic relationship between reaction velocity and substrate concentration. 4. multiple subunits and a sigmoid relationship between reaction velocity and substrate concentration. The figure below shows the relationship between % saturation of a solution of hemoglobin or myoglobin and the partial pressure of oxygen. There are three curves shown. You are not given any other information except that of the two curves which look similar in shape, the rightmost curve (C and D) is for pH = 7.2 and the leftmost curve (A and B) is for pH = 7.6. The next five questions are based upon this information and the figure. 11) Which point represents myoglobin under conditions where oxygen pressure is extremely low, such as during very strenuous exercise? 1. point A 2. point C 3. point X 4. point Y 5. point B 12) Which point represents myoglobin under normal conditions in a muscle cell? 1. point A 2. point C 3. point X 4. point Y 5. point B 13) Which point represents hemoglobin in the red blood cells flowing through the capillaries of the lung? 1. point A 2. point C 3. point X 4. point Y 5. point Z 14) Which point represents hemoglobin in the red blood cells flowing through the capillaries surrounding the muscle cells in the leg? 1. point A 2. point C 3. point X 4. point Y 5. point Z 15) Which curve describes the following relationship between % saturation (s) and partial pressure of oxygen (P): s = 100 P / (Constant + P)? 1. X - Y only 2. A - B only 3. C - D only 4. both A - B and C - D 5. all three curves follow the same relationship. 16) Which of the following is an integral component of the reactions which add glucose-1-phosphate to glycogen in the human liver? 1. UDPG 2. CTP 3. DEC 4. DHAP 5. RNAse 17) For each glucose molecule which begins glycolysis and ends with pyruvate, how many pyruvate molecules and how many net ATP molecules are produced? 1. 1 pyruvate and 2 ATP's for each glucose. 2. 2 pyruvates and 6 ATP's for each glucose. 3. 3 pyruvates and 2 ATP's for each glucose. 4. 1 pyruvate and 4 ATP's for each glucose. 5. 2 pyruvates and 2 ATP's for each glucose. 18) What sort of bonds might be found between molecules in gasoline or oil? 1. ionic bonds 2. hydrogen bonds 3. hydrophobic bonds 19) Which of the following is an allosteric inhibitor for aspartate transcarbamoylase? 1. UDPG 2. CTP 3. DEC 4. DHAP 5. ATP 20) The "endosymbiont hypothesis" refers to: 1. the origin of autotrophs. 2. the proposal that life was brought to Earth by spaceships or in meteorites. 3. splitting some primitive "bacteria" off into their own Kingdom. 4. the origin of glycolysis. 5. the origin of mitochondria. 21) Why might ammonia not be a good substitute for water in living systems on other planets? 1. Ammonia is hydrophobic, unlike water. 2. Ammonia is a poison. 3. Ammonia is a liquid only at very cold temperatures. 4. Ammonia is a large molecule and will not form a gas except at very high temperatures. 5. Ammonia is an unstable form of water, having an extra hydrogen covalently bonded to the central oxygen atom. 22) Which of the following is an effect of increased insulin concentrations on human liver cells? 1. No effect. Insulin does not bind to human liver cells. 2. Causes increased synthesis of glycogen. 3. Causes decreased synthesis of glycogen. 4. Causes increased synthesis of starch. 5. Causes decreased synthesis of starch. 23) A protein contains more than 50% of a single amino (or imino) acid. This acid has a residual side chain which loops back, binding to the amino nitrogen in addition to binding to the alpha carbon. What is the protein? 1. silk 2. keratin 3. hemoglobin 4. collagen 5. two or more of the above answers are equally correct. 24) What are GroEL and GroES? 1. carbohydrates 2. related to heat shock proteins. 3. non-protein groups which bind iron in hemoglobin or myoglobin. 4. powerful reducing agents used to break disulfide bonds in proteins. 5. hydrophobic non-protein materials used to denature proteins in the laboratory. 25) Which of the following most accurately describes V, the velocity of an enzyme-catalyzed reaction? 1. product concentration. 2. product concentration per second. 3. substrate concentration 4. substrate concentration per second. 5. the chemical rate constant of enzyme substrate formation plus the chemical rate constant of product formation. The figure below shows four different relationships (labeled A through D) between reaction velocity V and substrate concentration [S] for an enzyme catalyzed reaction. 26) Which of these relationships is applicable to an enzyme with the LARGEST number of cooperating subunits? 1. A 2. B 3. C 4. D 5. None of A, B, C, or D is correct. This enzyme must have only a single subunit. 27) Which of these relationships is applicable to an enzyme with only one subunit? 1. A 2. B 3. C 4. D 5. None of A, B, C, or D is correct. This enzyme must have multiple subunits. 28) What would you likely use mercaptoethanol for? 1. To disrupt and denature the structure of hemoglobin or myoglobin 2. To give a permanent wave to your hair, if you didn't care about serious effects on your body. 3. It is one of the intermediates in glycolysis so it might be used to simulate glycolysis in a test tube experiment. 4. It is a product of fermentation and is one of the materials which gives yogurt its characteristic taste. 29) Cysteine has which of the following side chains? 1. -H 2. - CH2 - SH 3. - CH2 - COOH 4. - CH2 - OH 30) Which of the amino acids characterized by the following side chains would be expected to be the MOST COMMON in keratin? 1. -H 2. - CH2 - SH 3. - CH2 - COOH 4. - CH2 - OH 31) Which of the following is the most accurate concerning the assumptions behind the Michaelis-Menten equation? 1. 2. 3. The substrate concentration must be much less than the enzyme concentration. A dynamic experiment in which enzyme-substrate concentration is changing with time is consistent with the assumptions of Michaelis-Menten theory. No inhibitors can bind to the enzyme 4. The enzyme must have a single catalytic site which does not interact with any other catalytic sites. 32) The Greek Key motif is 1. is characteristic of silk. 2. is characteristic of collagen 3. is a specific arrangement of 4 antiparallel protein chains 4. is a specific arrangement of 4 alpha-helices. 33) Which of the following proteins has NO cysteine and is composed of a high percentage of alpha helix? 1. silk 2. keratin 3. collagen 4. myoglobin. 5. ribonuclease 34) Which of the following proteins has a helical configuration which is stabilized by a large number of intra-chain hydrogen bonds? 1. silk 2. keratin 3. collagen 4. Answers 2 and 3 are equally correct. 5. All of answers 1, 2, and 3 are equally correct. 35) Which of the following proteins has a helical configuration which is stabilized primarily by intra-chain covalent bonds? 1. silk 2. keratin 3. collagen 4. Answers 2 and 3 are equally correct. 5. All of answers 1, 2, and 3 are equally correct. 36) Which of the following is the most accurate description of hydrophobic bonding? 1. Occurs only between electronegative and electropositive atoms. 2. Has a bond energy similar to that of a covalent bond. 3. 4. 5. Represents electron sharing between the hydrogen of one hydrocarbon molecule and the carbon of another. Hydrophobic bonds are not really bonds. Hydrophobic bonds involve attraction between a positively charged ion and a negatively charged ion. The figure below shows five panels, each demonstrating a particular kind of relationship between reaction velocity and substrate concentration for an enzyme-catalyzed reaction. For each case the solid line is the relationship in the absence of inhibitor or activator and the dotted line represents the relationship in the presence of inhibitor or activator. For the next four questions, select the panel which best describes the relationship given by the question. 37) Which panel describes the relationship between velocity and substrate concentration for a reaction catalyzed by an allosteric enzyme (solid line) and the same enzyme with an activator (dashed line)? 1. panel 1 2. panel 2 3. panel 3 4. panel 4 5. panel 5 38) Which panel describes the relationship between velocity and substrate concentration for a reaction catalyzed by a single subunit enzyme (solid line) and the same enzyme with an activator (dashed line)? 1. panel 1 2. panel 2 3. panel 3 4. panel 4 5. panel 5 39) Which panel describes the relationship between velocity and substrate concentration for a reaction catalyzed by a single subunit enzyme (solid line) and the same enzyme with a competitive inhibitor (dashed line)? 1. panel 1 2. panel 2 3. panel 3 4. panel 4 5. panel 5 40) Which panel describes the relationship between velocity and substrate concentration for a reaction catalyzed by a single subunit enzyme (solid line) and the same enzyme with a noncompetitive inhibitor (dashed line)? 1. panel 1 2. panel 2 3. panel 3 4. panel 4 5. panel 5 Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester - Second Examination - October 24 1996 Form 1 Note: This exam has been slightly shortened from the original. For all questions on membrane potentials, use T = 18 degrees C. 1) Which of the following is normally used to denature proteins when using gel electrophoresis? 1. DPN 2. polyacrylamide 3. mercaptoethanol 4. urea 5. SDS 2) Professor I. M. Anidiot is giving a lecture about optical microscopy. He clearly states that it is impossible to resolve structures which are shorter than about a quarter of the wavelength of light used. Which of the following is the most correct with regarding his statement? 1. No, by using a confocal microscope, one can "see" structures which are much smaller than the wavelength of the light used. 2. Professor Anidiot is correct. Structures smaller than about a quarter of the wavelength of light can never be resolved using light of that wavelength. 3. Professor Anidiot is correct but only with respect to light. If we built an X-ray microscope, we could resolve structures much smaller than a quarter of the wavelength of the X-rays. 4. We can "beat" the diffraction limit by placing a fiber optics probe very near the structure to be examined. In that way, the diffracted light will not spread very much. 3) True or False: X-ray diffraction can resolve structures which are significantly smaller than 10 nm in size. 1. True. 2. False. 4) What is the most likely reason for a positive afterpotential? 1. electrical capacitance. 2. an increase in sodium conductance during the course of the action potential. 3. an increase in potassium conductance during the course of the action potential. 4. positive afterpotentials are 5-10 mV depolarizations which occur as the direct result of transmitter binding to the postsynaptic membrane. 5. an increase in chloride conductance during the course of the action potential. 5) At the peak of the action potential, which of the following best describes the order of membrane permeabilities? 1. sodium (greatest), potassium (less), chloride (least). 2. chloride (greatest), sodium (less), potassium (least). 3. potassium (greatest), sodium (less), chloride (least). 4. sodium (greatest), chloride (less), potassium (least). 5. potassium (greatest), chloride (less), sodium (least). 6) What is most likely to happen if one blocks potassium channels on the nerve axon during stimulation of the nerve to produce action potentials? 1. The action potential will become shorter in duration. 2. The action potential will be blocked from ever beginning. 3. The action potential will become longer in duration. 4. Nothing will happen. The action potential does not depend on potassium permeability. 7) With which of the following answers is "phosphatidyl inositol" most closely associated? 1. It is a glycolipid. 2. It indicates ABO blood groups. 3. It is an important component of the TCA cycle. 4. It has long hydrocarbon tails attached to a glycerol backbone. 5. It is used as a component in gel electrophoresis. 8) With which of the following answers is "succinate" most closely associated? 1. A component of the electron transport chain, it accepts electrons from FADH2. 2. It is the component after citric acid in the TCA cycle. 3. Pyruvate is converted to succinate in lactic acid fermentation. 4. The complete name is "succinate dodecyl sulfate" or SDS. 5. None of answers 1, 2, 3 or 4 is correct. 9) With which of the following answers is "rotenone" most closely associated? 1. A component of the electron transport chain, it accepts electrons from FADH2. 2. It blocks the electron transport chain by preventing transfer of electrons to oxygen. 3. It is used as a pH buffer in gel electrophoresis. 4. It is a lipid, similar to cholesterol. 5. None of answers 1, 2, 3 or 4 is correct. 10) Assume that a cell membrane is equally permeable to potassium and chloride but impermeable to all other ions. If the concentration of potassium inside the cell is 50 mM, the concentration of potassium outside the cell is 100mM, and the concentration of chloride outside the cell is 5mM, what is the concentration of chloride inside the cell.? 1. 0.1mM. 2. 2.5mM. 3. 10mM. 4. 25mM. 5. 1000mM. 11) Assume that a cell membrane is equally permeable to potassium and iron (+3) but impermeable to all other ions. If the concentration of potassium inside the cell is 1 mM, the concentration of potassium outside the cell is 1 mM, and the concentration of iron outside the cell is 10mM, what is the concentration of iron inside the cell.? 1. 0.0001mM. 2. 0.1mM. 3. 2.5mM. 4. 10mM. 5. 1000mM. 12) On resting nerve cell membranes, what is the ratio of potassium conductance to sodium conductance (gK/gNa)? 1. 0.0001. 2. 0.01 3. 0.1 4. 10 5. 100. 13) Approximately, what is the duration of an action potential? 1. 2 microseconds. 2. 2 milliseconds 3. 0.2 seconds 4. 2 seconds 5. On nerve axons, it is highly variable. In some cases it may be as long as 20 milliseconds. In other cases, it may be as short as 0.5 milliseconds. 14) Lipids which are broken down enter the reactions of glycolysis, the TCA cycle, and electron transport chain: 1. by being broken down into three carbon molecules which enter the reactions of the TCA cycle as pyruvate. 2. by being broken down into two carbon molecules which enter the reactions of the TCA cycle as acetyl-CoA. 3. by being broken down into four carbon molecules which enter the reactions of the TCA cycle as oxaloacetate. 4. Lipids are broken down into 6 carbon sugars which enter the reactions of glycolysis. 5. Lipid breakdown produces NADPH, quite independently of any reactions in glycolysis and the TCA cycle. The NADPH then is used by the electron transport chain to make ATP. 15) Typically, what is the value of the sodium Nernst potential? 1. -56 microVolts 2. +56 microVolts 3. -56 milliVolts 4. +56 milliVolts 5. zero 16) Typically, what is the Sodium concentration in human blood plasma? 1. 120 millimolar. 2. 10 millimolar. 3. 120 micromolar. 4. 10 micromolar. 5. 1 micromolar 17) With which of the following answers is "lecithin" most closely associated? 1. It is a glycolipid. 2. It indicates ABO blood groups. 3. It is an important component of the TCA cycle. 4. It has long hydrocarbon tails attached to a glycerol backbone. 5. It is used as a component in gel electrophoresis. 18) True or False: Transverse movement of membrane lipids, from the outside surface of a cell membrane to the inside surface, is characterized by a viscosity approximately equal to that of olive oil. 1. True. 2. False. 19) You land on a distant planet and find that cells on that plant have only one ion - Calcium, which is permeable across cell membranes. Calcium concentrations are: [Ca+2]inside = 0.1 mM and [Ca+2]outside = 10 mM. What is the potential across the membrane (inside)? 1. +29 mV 2. -58 mV 3. +58 mV 4. -87 mV 5. -174 mV. 20) While doing some research on a newly discovered marine invertebrate, you find that its cells are only permeable to one type of ion. But you do not know what ion it is. You determine that the concentration of this ion inside the cells is 100 mM and the concentration outside the cells is 0.1 mM. The membrane potential is -58 mV. Which of the following is most likely the ion in question? 1. Iron (+3) 2. Potassium (+1) 3. Calcium (+2) 4. Phosphate (-2) 5. Chloride (-1) 21) True or False: An electron microscope doesn't damage the sample being observed because, unlike X-rays, electrons don't have any mass and thus don't cause so much damage. 1. True. 2. False. 22) Why does gel electrophoresis work for measurements of the molecular weight of proteins? 1. It only works on proteins which are spherical in their native configuration. For these proteins, the speed of movement can be related to the volume of the particle and thus molecular weight. 2. Proteins are first made into a random coil configuration. In the random coil, the diameter of the "coil" can always be related to molecular weight, independent of the shape of the particle in the native configuration. 3. Gel electrophoresis measures something called the sedimentation coefficient, not molecular weight. 4. Gel electrophoresis measures permeability through a membrane, not molecular weight. 23) Which is most accurate concerning membrane phospholipids of animal cells? 1. Have mostly saturated hydrophobic chains with 16 to 20 carbons. 2. Have mostly saturated hydrophobic chains with 6 to 10 carbons. 3. Have mostly unsaturated hydrophobic chains with 16 to 20 carbons. 4. Have mostly unsaturated hydrophobic chains with 6 to 10 carbons. 24) Which of the following is made by substrate-level phosphorylation in the TCA cycle? 1. ATP only 2. ATP and GTP 3. GTP only 4. NADH, FADH2, and GTP 5. none of ATP, GTP, NADH, or FADH2. 25) Which of the following is made by substrate-level phosphorylation in the electron transport chain? 1. ATP only 2. ATP and GTP 3. GTP only 4. NADH, FADH2, and GTP 5. none of ATP, GTP, NADH, or FADH2. 26) For the pyruvate dehydrogenase complex, immediately before the reactions of the TCA cycle, which of the following is most accurate. (For purposes of the question, begin the cycle at the point where pyruvate enters.) 1. Acetyl-CoA is made before carbon dioxide is released. 2. NADH is produced after Acetyl-CoA is made. 3. Carbon dioxide is released and FADH2 is produced simultaneously. Acetyl-CoA is made later. 4. Carbon dioxide is made from one of the carbons of the acetyl fragment in Acetyl-CoA. 5. FADH2 is produced after carbon dioxide is released. 27) Which of the following reactions releases the most free energy? (For simplicity, only the most important components of the reaction are shown.) 1. FADH2 -> FAD 2. NADH -> NAD+ 3. ATP -> ADP 28) You are studying membrane transport of a newly discovered small molecule. You find that this molecule always moves from regions of higher concentration to regions of lower concentration, regardless of whether the region of highest concentration is the cytoplasm or the external environment of the cell. You find that as you increase the concentration difference between the inside and outside of the cell, the rate of movement of the molecule across the membrane increases. However, as the concentration difference increases to large values, the rate of movement across the membrane appears to reach a limiting maximum value. What is the most likely mechanism for the membrane transport? 1. Fick's law thermal diffusion. 2. facilitated diffusion. 3. active transport 4. American Airlines 29) You are studying membrane transport of a newly discovered small molecule. You find that this molecule always moves from a region of lower concentration to a region of higher concentration. You find that as you increase the concentration difference between the inside and outside of the cell, the rate of movement of the molecule across the membrane increases. However, as the concentration difference increases to large values, the rate of movement across the membrane appears to reach a limiting maximum value. What is the most likely mechanism for the membrane transport? 1. Fick's law thermal diffusion. 2. facilitated diffusion. 3. active transport 4. American Airlines 30) You are studying movement of a molecule across a cell membrane. You know that this movement obeys Fick's law, simple thermal, diffusion. Initially, the influx J = 1.5 micromoles/sec-cm2 for an external concentration of 2 mM and an internal concentration of 0.5 mM. Suppose now that the external concentration was halved to 1 mM and the internal concentration remained at 0.5 mM. What would the flux be under the new conditions? 1. 0.75 micromoles/sec-cm2 2. 0.375 micromoles/sec-cm2. 3. 3.0 micromoles/sec-cm2 4. 0.50 micromoles/sec-cm2 5. 0.25 micromoles/sec-cm2 31) Which of the following could best be described as a process directly involving facilitated diffusion of glucose with cotransport of sodium? 1. movement across the serosal size of the intestinal epithelium 2. electron transport chain in mitochondria 3. glyceraldehyde-phosphate shuttle 4. malate shuttle 5. none of answers 1, 2, 3, or 4 are correct. 32) Where is the TCA cycle located? 1. Cytoplasm, not in mitochondria or chloroplasts 2. matrix of mitochondria 3. outer membrane of mitochondria 4. inner membrane of mitochondria 33) Where is the electron transport chain located? 1. Cytoplasm, not in mitochondria or chloroplasts 2. matrix of mitochondria 3. outer membrane of mitochondria 4. inner membrane of mitochondria 34) Where is glycolysis located? 1. Cytoplasm, not in mitochondria or chloroplasts 2. matrix of mitochondria 3. outer membrane of mitochondria 4. inner membrane of mitochondria 35) In human liver cells, which of the following is most accurate concerning the movement of NADH's reducing power, produced by glycolysis, into the mitochondrion? 1. NADH moves down its concentration gradient, into the mitochondrion, freely. 2. NADH produced by glycolysis is always used up in fermentation. 3. NADH does not move into the mitochondrion, but some of the reducing power does produce FADH2 inside the mitochondrion. 4. NADH is not produced by reactions of glycolysis. 36) Which of the following best describes the action of the Na+/K+ pump? 1. For each ATP used, 1 sodium ion is pumped out from the cell and 1 potassium ion is pumped into the cell. 2. For each ATP used, 3 sodium ions are pumped into the cell and 2 potassium ions are pumped out from the cell. 3. For each ATP used, 2 sodium ions are pumped into the cell and 3 potassium ions are pumped out from the cell. 4. For each ATP used, 3 sodium ions are pumped out from the cell and 2 potassium ions are pumped into the cell. 5. For each ATP used, 2 sodium ions are pumped out from the cell and 3 potassium ions are pumped into the cell. 37) Which of the following best describes osmosis? 1. Osmosis is Fick's law, simple thermal diffusion except that water diffuses from regions in which it is in lower concentration to regions in which it is in higher concentration. 2. Osmosis is Fick's law, simple thermal diffusion. Water diffuses from regions in which it is in higher concentration to regions in which it is in lower concentration. 3. Osmosis is a completely different process from Fick's law diffusion and so neither of the first two answers is correct. Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Fall Semester - Third Examination - November 21, 1996 Form 1 1) Which of the following is a protein found on the thin filaments of human muscle, which binds Calcium resulting in activation of muscle contraction? 1. tropomyosin. 2. actin. 3. myosin. 4. alpha-actinin. 5. troponin. 2) Professor H. E. Knowital is giving a lecture on photosynthesis. He states that the "chemiosmotic scheme is used in the light-independent reactions of photosynthesis, actively pumping hydrogen ions from the interior of the grana into the stroma, using the energy derived from the light to do so". Which of the following is most accurate concerning this statement? 1. There is no pumping of hydrogen ions related to photosynthesis. 2. Hydrogen ions are pumped from the grana into the stroma, but only in the light-dependent reactions. 3. Hydrogen ions are pumped from the stroma into the grana, but only in the light-dependent reactions. 4. Hydrogen ions are pumped from the stroma into the grana, but only in the light-independent reactions. 5. Professor Knowital is absolutely correct! 3) In chloroplasts, which is the equivalent compartment to the intermembrane compartment of mitochondria? When considering "equivalence", examine particularly the directionality of the functions of the chemiosmotic scheme. 1. stroma 2. cisternae of sarcoplasmic reticulum 3. interior of grana 4. cisternae of Golgi 4) Which of the following is a protein found as a principal component of the interior of Z-disks, and binds to thin filaments, holding them to the Z-disk? 1. tropomyosin. 2. tubulin. 3. dynein. 4. alpha-actinin. 5. troponin. 5) Which of the following is an enzyme which catalyzes the dephosphorylation of ATP, coupled with the generation of force in a contractile process? 1. tropomyosin. 2. tubulin. 3. dynein. 4. alpha-actinin. 5. troponin. 6) Which of the following is the principal protein, mentioned in class, which binds thin filaments of smooth muscle to components of the cell membrane? 1. tropomyosin. 2. tubulin. 3. dynein. 4. alpha-actinin. 5. troponin. 7) With which of the following is the term "Kranz anatomy" most closely associated? 1. Golgi apparatus. 2. Bundle sheath cells. 3. Striated skeletal muscle. 4. Succulent plants, such as cacti. 8) Which of the following is most closely associated with "photorespiration"? 1. Oxygen gas is a substrate for Ribulose-1-5-bisphosphate carboxylase. 2. Lohman reaction. 3. light dependent reactions of photosynthesis. 4. Tay-Sachs' disease. 9) Detoxification of barbituates is thought to take place in the: 1. mitochondria. 2. lysosomes. 3. smooth endoplasmic reticulum. 4. rough endoplasmic reticulum. 5. bundle sheath cells. 10) True or False: Chlorophyll is a protein. 1. True. 2. False. 11) Combined with the basic structure of chlorophyll is an atom of: 1. Iron 2. Manganese. 3. Calcium. 4. Magnesium. 5. None of the above are a part of chlorophyll. 12) "Storage Diseases" are associated with failure of normal processes of: 1. protein synthesis on the rough endoplasmic reticulum. 2. endocytosis. 3. cytokinesis. 4. Golgi. 5. lysosomes. 13) The following question is with respect to the actin/myosin/ATP kinetics discussed in class. A is for actin, M is for myosin, AM is actin bound to myosin, P is inorganic phosphate ion. The * indicates that components are bound together. During which step of the reaction scheme is the energy released by hydrolysis of ATP thought to be stored in the myosin molecule? 1. AM*ADP*P -> AM + ADP + P 2. M*ADP*P -> M + ADP + P 3. M*ATP -> M*ADP*P 4. AM*ATP -> AM*ADP*P 5. AM + ATP -> AM*ATP 14) The following question is with respect to the actin/myosin/ATP kinetics discussed in class. A is for actin, M is for myosin, AM is actin bound to myosin, P is inorganic phosphate ion. The * indicates that components are bound together. During which step of the reaction scheme is it thought that the myosin cross bridges involved in creating force during normal contraction actually bend and release the stored energy to produce muscle shortening? 1. AM*ADP*P -> AM + ADP + P 2. M*ADP*P -> M + ADP + P 3. M*ATP -> M*ADP*P 4. AM*ATP -> AM*ADP*P 5. AM + ATP -> AM*ATP 15) The following question is with respect to the actin/myosin/ATP kinetics discussed in class. A is for actin, M is for myosin, AM is actin bound to myosin, P is inorganic phosphate ion. The * indicates that components are bound together. Which step in this reaction scheme is VERY slow (compared with other reaction steps) when the muscle is relaxed? 1. AM*ADP*P -> AM + ADP + P 2. M*ADP*P -> M + ADP + P 3. M*ATP -> M*ADP*P 4. AM*ATP -> AM*ADP*P 5. AM + ATP -> AM*ATP 16) The following question is with respect to the actin/myosin/ATP kinetics discussed in class. A is for actin, M is for myosin, AM is actin bound to myosin, P is inorganic phosphate ion. The * indicates that components are bound together. When muscle goes into rigor, it is the result of one of the key reaction not being able to proceed. Which of the following reactions is that key reaction? 1. AM*ADP*P -> AM + ADP + P 2. M*ADP*P -> M + ADP + P 3. M*ATP -> M*ADP*P 4. AM*ATP -> AM*ADP*P 5. AM + ATP -> AM*ATP 17) The following question is with respect to the actin/myosin/ATP kinetics discussed in class. A is for actin, M is for myosin, AM is actin bound to myosin, P is inorganic phosphate ion. The * indicates that components are bound together. Which of the following reactions does not occur in the myofibrils of human skeletal muscle? 1. AM*ADP*P -> AM + ADP + P 2. M*ADP*P -> M + ADP + P 3. M*ATP -> M*ADP*P 4. AM*ATP -> AM*ADP*P 5. AM + ATP -> AM*ATP 18) Which best describes T-tubules in human skeletal muscle? 1. The membranes of the T-tubules are contiguous with the membranes of the sacroplasmic reticulum. 2. The membranes of the T-tubules are contiguous with the external cell membrane and run transversely only near the Z-lines. 3. The membranes of the T-tubules are contiguous with the external cell membrane and run transversely only near the center of the sarcomere. 4. The membranes of the T-tubules are contiguous with the external cell membrane and run transversely only near the end plate (synapse). 5. The membranes of the T-tubules are contiguous with neither with those of the sarcoplasmic reticulum nor the external cell membrane. 19) Suppose we divide the visible light spectrum into the three regions given as a answers to this question. In which of these regions does chlorophyll absorb light the least? 1. 400 - 500 nm. 2. 501 - 600 nm. 3. 601 - 700 nm. 20) Which of the following distinguishes a principal form in which chemical energy is stored and used in photosynthesis from the way it is stored and used in heterotropic metabolism, such as the TCA cycle and electron transport chain? 1. GTP is produced by the light reactions - ATP is NOT produced 2. FADH2 is produced by the light reactions instead of NADH or NADPH. 3. NADPH is produced by the light reactions instead of NADH. 21) Which of the following processes is most likely to be inhibited by Cytochalasin B? 1. cytokinesis. 2. protein synthesis on the rough endoplasmic reticulum. 3. light reactions of photosynthesis. 4. movement of prokaryotic cilia or flagella 5. chromosome movement. 22) Which of the following is the LOWEST concentration, of those given in the answers, of free calcium in the interior of the myofibrils of human skeletal muscle which will activate muscle contraction? 1. 10-10 mM. 2. 10-7 mM. 3. 10-3 mM. 4. 10-1 mM. 23) True or False: The A-band shortens in length during muscle contraction. 1. True. 2. False. 24) True or False: The I-band shortens in length during muscle contraction. 1. True. 2. False. 25) True or False: The distance between Z-lines (disks) shortens during muscle contraction. 1. True. 2. False. 26) Which answer best describes desmin? 1. A protein which spirals down the groove on both sides of the actin helix and covers myosin binding sites when muscle is relaxed. 2. an important substrate in the Calvin-Benson cycle. 3. only found in C4 plants. 4. found on the periphery of the Z-disks. 5. gives rough endoplasmic reticulum its "roughness". 27) Which answer best describes the mechanism for chromosome movement in animal cells? 1. Microtubules which slide relative to each other, powered by myosin movement. 2. Microtubules which slide relative to each other, powered by dynein movement. 3. Microfilaments which slide relative to each other, powered by myosin movement. 4. Microfilaments which slide relative to each other, powered by dynein movement. 5. Shortening of microtubules, without use of dynein or myosin. 28) Where is the 9+2 structure found? 1. Only in prokaryotic cilia and flagella. 2. Only in eukaryotic cilia and flagella. 3. In both prokaryotic and eukaryotic cilia and flagella. 4. Only in vertebrate skeletal muscle cells. 5. Only associated with some unusual structures, such as the axostyle of microorganisms found in the wood roach. 29) Where would you find a tubulin heterodimer? 1. In the contractile ring. 2. In the A-band of striated skeletal muscle. 3. In the I-band of striated skeletal muscle. 4. In eukaryotic cilia and flagella. 5. In prokaryotic cilia and flagella. 30) In chloroplasts, which is the equivalent compartment to the matrix of mitochondria? When considering "equivalence", examine particularly the directionality of the functions of the chemiosmotic scheme. 1. stroma 2. cisternae of sarcoplasmic reticulum 3. interior of grana 4. cisternae of Golgi 31) Which of the following is most correct with respect to the synthesis and release of insulin? 1. 2. 3. Insulin is manufactured on free polyribosomes in the cytoplasm. Insulin is manufactured on the rough endoplasmic reticulum, packaged in vesicles, and exocytosed directly. Insulin is actually manufactured as proinsulin. Proinsulin is converted to insulin in the Golgi. 4. Insulin is not a protein. But, it is processed in the Golgi and exocytosed in vesicles. 32) Which of the following processes is most likely to be inhibited by Colchicine? 1. cytokinesis. 2. protein synthesis on the rough endoplasmic reticulum. 3. light reactions of photosynthesis. 4. movement of prokaryotic cilia or flagella 5. chromosome movement. 33) Which of the following is most accurate with respect to the effects of asbestos on the epithelial cells in the lungs? 1. Asbestos has its most serious effects by puncturing the external cell membranes and causing osmotic death of the cells. 2. Asbestos is endocytosed into the cells and winds up in vesicles together with lysosomal enzymes. 3. Asbestos binds to the ribosomes on the rough endoplasmic reticulum and prevents them from synthesizing protein. 4. Asbestos binds to nuclear DNA and prevents transcription. 5. Asbestos causes a storage disease - It cannot be broken down so it just keeps building up. It has no other effect. 34) How is it determined whether a protein will be manufactured for export from the cell or used internally as a cytoplasmic protein? 1. If the protein is to be exported, the first part of the protein sequence manufactured permits the ribosome to bind to the endoplasmic reticulum membrane. 2. Proteins manufactured for export are manufactured on free polyribosomes in the cytoplasm like all proteins. The difference is that proteins which are to be exocytosed will bind to the external cell membrane while cytoplasmic proteins will not. 3. Proteins manufactured for export are made by ribosomes which are bound to the external cell membrane. As the proteins are made, they pass through a hole in the ribosome and cell membrane into the exterior. 4. Proteins manufactured for export are made in the lysosome interior, then exocytosed. 35) What is TGN? 1. A four carbon molecule associated with C4 photosynthesis. 2. One of the units of troponin. 3. The enzymatic component of the M-line. 4. The special part of the Golgi facing the external cell membrane. 5. A component of the protein translocator system on the rough endoplasmic reticulum. 36) Rheumatoid arthritis is: 1. A storage disease. 2. An autoimmune disease. 3. A degenerative muscle disease caused by loss of muscle protein. 4. caused by failure of cells to make and exocytose collagen. 5. caused by degeneration of the Golgi. 37) True or False: "C4 photosynthesis replaces the normal Calvin-Benson cycle with a new cycle involving four carbon molecules. C4 plants do not have the Calvin-Benson cycle." 1. True. 2. False. 38) With which of the following would you expect to find "clathrin" associated? 1. thick or thin filaments of skeletal muscle. 2. prokaryotic cilia or flagella. 3. C4 photosynthetic reactions. 4. light-dependent reactions of photosynthesis. 5. endocytosis. Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Second Summer Session - First Examination 11 July, 1996 Choose the best or most complete and accurate answer. 1) The Sodium/Potassium pump: 1. transports three Sodium ions out and two Potassium in for every ATP used. 2. transports two Sodium ions out and three Potassium in for every ATP used. 3. transports three Sodium ions in and one Potassium out for every ATP used. 4. transports two Sodium ions in and three Potassium out for every ATP used. 2) Which is most likely accurate concerning the atmosphere of the earth before the first cells appeared? 1. High concentrations of Carbon Dioxide and Nitrogen gases. 2. A strongly reducing atmosphere 3. Very little hydrogen gas. 4. Answers 1 and 2 are equally correct. 5. All of answers 1, 2, and 3 are equally correct. 3) True or False: In general, more oily molecules pass through cell membranes more easily. 1. True 2. False 4) Which of the following best describes urea? 1. a protein 2. a polysaccharide composed mostly of glucose subunits 3. a detergent used in scientific experimentation. 4. a powerful reducing agent 5. disrupts normal hydrophobic bonding in proteins and causes denaturation. 5) Which of the following best describes cellulose? 1. a protein 2. a polysaccharide composed mostly of glucose subunits 3. a detergent used in scientific experimentation. 4. a powerful reducing agent 5. disrupts normal hydrophobic bonding in proteins and causes denaturation. 6) Which of the following would best be measured by SDS polyacrylamide gel electrophoresis? 1. sedimentation coefficient 2. molecular dimensions 3. molecular weight 4. optical absorbance 7) Approximately, what is the ratio of the diameter of the smallest living cells to the shortest wavelength of visible light? 1. 8 2. 100 3. 0.001 4. 0.13 5. 0.01 8) What is the purpose of treating samples with SDS when doing polyacrylamide gel electrophoresis 1. SDS cleans the dialysis tubing used to contain the eletrophoresis gel. 2. SDS is a powerful oxidizing agent and thus breaks disulfide bonds. 3. SDS is the molecule which binds together parts of the gel. 4. SDS denatures proteins. 5. SDS stands for Scientific Data Systems, the company which makes much of the gel used in scientific research. 9) True or False: It is has been impossible to build an apparatus which uses visible light to view details of structure which are much smaller than the wavelength of the light used. 1. True 2. False 10) Which of the following best describes GroEL? 1. a polysaccharide composed mostly of glucose subunits 2. a detergent used in scientific experimentation. 3. a protein 4. a powerful reducing agent 5. disrupts normal hydrophobic bonding in proteins and causes denaturation. 11) Which of the following best describes mercaptoethanol? 1. a polysaccharide composed mostly of glucose subunits 2. a detergent used in scientific experimentation. 3. a powerful reducing agent 4. disrupts normal hydrophobic bonding in proteins and causes denaturation. 5. a protein 12) Which of the following directly participates in the reaction which adds glucose to a growing glycogen chain? 1. ATP 2. NADH 3. FADH2 4. GTP 5. UTP 13) Which of the following is the only tissue in the human body which uses fermentation to produce ethanol from pyruvate? 1. liver 2. neurons 3. kidney 4. muscle 5. None of the above are correct answers. 14) Most proteins absorb which of the following types of light most strongly? 1. blue 2. green 3. red 4. ultraviolet 5. yellow 15) DNA and RNA absorb which of the following types of light most strongly? 1. blue 2. green 3. red 4. ultraviolet 5. yellow 16) Which of the following is most accurate with respect to the step in glycolysis in which NAD+ is made from NADH? 1. Involves conversion of one 6 carbon carbohydrate to another 6 carbon carbohydrate and simultaneous reaction of one ATP to form ADP and phosphate. 2. Involves conversion of one 6 carbon carbohydrate to another 6 carbon carbohydrate WITHOUT reaction of ADP or ATP. 3. Involves conversion of one 3 carbon carbohydrate to another 3 carbon carbohydrate and simultaneous reaction of one ATP to form ADP and phosphate. 4. Involves conversion of one 3 carbon carbohydrate to another 3 carbon carbohydrate WITHOUT reaction of ADP or ATP. 5. No NAD+ is made from NADH in the reactions of glycolysis. 17) Which of the following is most accurate with respect to the enzyme which breaks down and thus detoxifies ethanol in the human body ? 1. A noncompetitive inhibitor is ethylene glycol. 2. A substrate is oxalic acid. 3. A substrate is ethylene glycol. 4. An uncompetitive inhibitor is ethylene glycol. 5. An uncompetitve inhibitor is oxalic acid. 18) Collagen is: 1. a protein with an alpha helical structure 2. an antiparallel beta pleated sheet 3. held in a helical configuration by covalent bonds. 4. Both answers 1 and 3 are equally correct. 5. None of the answers 1, 2, or 3 are correct. 19) The mycoplasma are 1. Archebacteria. 2. Cyanobacteria. 3. Autotrophic. 4. Eukaryotic. 5. None of the above answers are correct. 20) What is the diameter of the smallest mycoplasma? 1. 0.05 meter 2. 0.05 millimeter 3. 0.05 micrometer 4. 0.05 nanometer 5. None of the above answers are correct. 21) For an enzyme which obeys Michaelis-Menten kinetics, suppose that the reaction velocity is 3/4 of maximum. What is the substrate concentration if the Michaelis constant is 2 mM (millimolar)? 1. 6 mM 2. 3 mM 3. 2 mM 4. 1/3 mM 5. None of the above answers are correct. 22) For an enzyme which obeys Michaelis-Menten kinetics, at what substrate concentration is V/Vmax = 1/4? 1. Km 2. Km/5 3. Km/3 4. Km/4 5. None of the above are correct answers 23) For an enzyme which obeys Michaelis-Menten kinetics, which of the following is most accurate? 1. Free enzyme (not bound to substrate) concentration is in equilibrium. 2. Enzyme concentration is high relative to substrate concentration. 3. Product can combine with enzyme to produce substrate. 4. Enzyme-substrate concentration remains almost constant. 5. None of the above are correct answers 24) Silk is: 1. a protein with an alpha helical structure 2. an antiparallel beta pleated sheet 3. held in a helical configuration by covalent bonds. 4. Both answers 1 and 3 are equally correct. 5. None of the answers 1, 2, or 3 are correct. 25) The protein of which human hair is primarily composed is: 1. a protein with an alpha helical structure 2. an antiparallel beta pleated sheet 3. held in a helical configuration by covalent bonds. 4. Both answers 1 and 3 are equally correct. 5. None of the answers 1, 2, or 3 are correct. 26) For an enzyme which obeys Michaelis-Menten kinetics, which of the following is most accurate as one raises the concentration of a competitive inhibitor? 1. The apparent Vmax decreases but the apparent Km does not change. 2. The apparent Vmax increases but the apparent Km does not change. 3. The apparent Vmax does not change but the apparent Km decreases. 4. The apparent Vmax does not change but the apparent Km increases. 5. Both the apparent Vmax and apparent Km decrease. 27) For an enzyme which obeys Michaelis-Menten kinetics, which of the following is most accurate as one raises the concentration of an uncompetitive inhibitor? 1. The apparent Vmax decreases but the apparent Km does not change. 2. The apparent Vmax increases but the apparent Km does not change. 3. The apparent Vmax does not change but the apparent Km decreases. 4. The apparent Vmax does not change but the apparent Km increases. 5. Both the apparent Vmax and apparent Km decrease. 28) For an enzyme which obeys Michaelis-Menten kinetics, which of the following is most accurate as one raises the concentration of a noncompetitive inhibitor? 1. The apparent Vmax decreases but the apparent Km does not change. 2. The apparent Vmax increases but the apparent Km does not change. 3. The apparent Vmax does not change but the apparent Km decreases. 4. The apparent Vmax does not change but the apparent Km increases. 5. Both the apparent Vmax and apparent Km decrease. 29) Reduction of NADH to produce NAD+ releases how much Gibbs' energy? 1. Enough to phosphorylate one ADP to ATP. 2. Enough to phosphorylate two ADPs to ATPs. 3. Enough to phosphorylate three ADPs to ATPs. 4. Enough to phosphorylate four ADPs to ATPs. 5. NADH is the reduced form of NAD and NAD+ is the oxidized form. 30) Glycogen is: 1. a protein with an alpha helical structure 2. an antiparallel beta pleated sheet 3. held in a helical configuration by covalent bonds. 4. Both answers 1 and 3 are equally correct. 5. None of the answers 1, 2, or 3 are correct. 31) The first eukaryotes are thought to 1. 2. have first appeared 3.5 billion years ago. have been more similiar to present day Archebacteria than to any other presently living organism. 3. to have been made in Carl Sagan's laboratory at Cornell University. 4. have evolved from a symbiotic relationship between two different prokaryotes. 5. have been bacteria which developed mitochondria derived from their own mesosomes. 32) You measure reaction velocity vs. substrate concentration for an allosteric enzyme. Which of the following is most accurate? 1. 2. 3. The Lineweaver-Burke plot will be a straight line. The Lineweaver-Burke plot will appear to reach a maximum at high values for the reciprocal of substrate concentration. The reciprocal of reaction velocity will increase with increasing substrate concentration. 4. A plot of reaction velocity vs. substrate concentration will be sigmoid (S-shaped). 33) Which of the following is a phospholipid with a polar end consisting of a choline group? 1. cholesterol 2. glycophorin 3. lecithin 4. spectrin 5. sialic acid 34) Which of the following is a is a common membrane lipid which is not a phospholipid? 1. cholesterol 2. glycophorin 3. lecithin 4. spectrin 5. sialic acid 35) True or False: Most membrane phospholipids are polyunsaturated. 1. True 2. False 36) Which of the following causes hemoglobin to release bound oxygen? 1. lower oxygen pressure 2. increased pH (higher numerical value) 3. more bicarbonate bound to hemoglobin 4. two of 1, 2, or 3 are equally correct answers 5. all of 1, 2, or 3 are equally correct answers 37) Which of the following is most closely associated with transport of carbon dioxide from the peripheral tissues back to the lungs? 1. glycophorin 2. hemoglobin 3. band 3 protein 4. band 4.1 protein 5. GroEL 38) Which of the following is an intrinsic (integral) membrane protein with a single alpha helix which passes through the membrane? 1. glycophorin 2. hemoglobin 3. band 3 protein 4. band 4.1 protein 5. GroEL 39) True or False: The viscosity of cell membranes with respect to molecules passing from the outside of the membrane to the inside is very near that of the same molecules moving through olive oil. 1. True 2. False 40) Ammonia would probably not be a good substitute for water if ammonia-based life were to begin to evolve on another planet because: 1. Liquid ammonia, such as that bought at the supermarket, is inherently toxic to life. 2. Ammonia, unlike water, floats when frozen. 3. Ammonia does not form hydrogen bonds. 4. Ammonia only exists in the liquid state at temperatures below -33 degrees centigrade. 5. Ammonia does not contain any nitrogen. 41) Your friend is trying to sell you a container of hexoses. What is in the container? 1. high energy glucose tablets 2. fat 3. wood 4. glycerol 5. A bad luck charm. 42) You observe the following characteristics of the influx of radioactive gablose into human liver cells: Influx increases as concentration of gablose outside the cell increases but reaches a maximum rate as the concentration of gablose increases to high values. Which of the following can you say with certainty, if the information given here is all you know? 1. The movement must be by either facilitated diffusion or active transport. 2. The movement must be by facilitated diffusion 3. The movement must be by either simple thermal diffusion or active transport. 4. The movement must be by active transport 5. The movement must be by simple thermal diffusion 43) Movement of glucose across the serosal membrane of human intestinal epithelial cells is normally 1. by facilitated diffusion co-transport with potassium 2. down the concentration gradient for glucose - from high to low glucose concentration. 3. by active transport 4. by phosphorylation of glucose inside the epithelial cells and release of the phosphorylated glucose into the bloodstream. 5. through a V-type ion pump. 44) You are plotting 1/V vs. 1/[S] for an enzyme which obeys Michaelis- Menten kinetics. (V is reaction velocity and S is substrate concentration.) As you increase inhibitor concentration, the slope of the line on the plot does not change. What kind of inhibitor are you using? 1. one which binds to the active site. 2. one which binds to a site on the enzyme which is distinct from the active site. 3. one which binds only to the enzyme-substrate complex. 45) Approximately what is the concentration of sodium ions in the blood plasma of a frog? 1. 0.1 mM 2. 10 mM 3. 100mM 4. 1000 mM 5. 1 micromolar 46) Approximately what is the concentration of potassium ions in the blood plasma of a frog? 1. 0.1 mM 2. 10 mM 3. 100mM 4. 1000 mM 5. 1 micromolar 47) What would happen if you poisoned the Na+/K+ pump so that it ceased to function? 1. The cells would fill up with potassium. 2. Cells would fill up with glucose. 3. Sodium concentration within cells would drop. 4. The cells would shrink. 5. Cells would expand and possibly burst. 48) Which of the following is an inhibitor for Phosphofructokinase, the enzyme which catalyzes the reaction, Fructose 6-phosphate --> Fructose 1,6,-bisphosphate, in glycolysis? 1. long chain fatty acids 2. Citrate 3. AMP 4. Either long chain fatty acids or citrate are inhibitiors. 5. All of long chain fatty acids, citrate, and AMP are inhibitors. 49) Suppose we have a molecule which diffuses across cell membranes according to Fick's law for simple thermal diffusion. The concentration of this molecule inside the cell is much less than it is outside. If the concentration of the molecule outside the cell is doubled, what will happen to the influx? 1. It must double. 2. It must decrease to half its previous value. 3. It must go up, but not necessarily double. 4. It may go up or down. We cannot tell 50) Cyanide is a metabolic poison which effectively stops ATP production by mitochondia. If we poison a cell with Cyanide, which of the following is most likely as an immediate effect? 1. Potassium efflux will sharply decrease. 2. Sodium efflux will sharply decrease. 3. Chloride influx will sharply decrease. Press to SUBMIT or CLEAR to redo the exam Error cannot open input file!!! /usr/ns-home/docs/Faculty/Tom/Exams/255sum96e2.tie Bil 255, Cell Biology - Second Summer Session - Second Examination - 26 July, 1996 Choose the best or most complete and accurate answer. 1) True or False: In eukaryotes, NADH produced by glycolysis can freely diffuse into the mitochondria. 1. True 2. False 2) Kranz anatomy is associated most closely with which of the following? 1. mitochondria 2. T-tubules 3. leaves 4. Golgi apparatus 5. storage disease 3) Which of the following is a five carbon sugar which is a key intermediate participating directly in the reactions of the TCA cycle? 1. Ribulose-1,5-bisphosphate 2. Dihydroxyacetone phosphate 3. Glycogen 4. Fructose-1,6-bisphosphate 5. None of 1, 2, 3, or 4 are correct answers. 4) In all higher plants which do photosynthesis, which of the following combines with Carbon Dioxide to produce 3-phosphoglycerate ? 1. Ribulose-1,5-bisphosphate 2. Dihydroxyacetone phosphate 3. Glycogen 4. Fructose-1,6-bisphosphate 5. None of 1, 2, 3, or 4 are correct answers. 5) True or False: If only cyclic photophosphorylation, and NO other light dependent reactions, are taking place, will Oxygen be produced? 1. Yes 2. No 6) Where is chorophyll located? 1. stroma 2. matrix 3. inner membrane of mitochondria 4. thylakoids 5. lysosomes 7) Which of the following is a disease which involves a missing enzyme in human lysosomes? 1. beri-beri 2. bovine spongiform encephalopathy (mad cow disease) 3. Tay-Sach's disease 4. Lou Gehrig's disease 5. rigor mortis 8) Which of the following is a disease which occurs because of a thiamine deficiency? (Thiamine is also called vitamin B1.) 1. beri-beri 2. bovine spongiform encephalopathy (mad cow disease) 3. Tay-Sach's disease 4. Lou Gehrig's disease 5. rigor mortis 9) True or false: NADH is a product of the light dependent reactions of photosynthesis. 1. True 2. False 10) True or false: In eukaryotes, pyruvate produced by glycolysis can freely diffuse into the mitochondria. 1. True 2. False 11) Which of the following is most correct with respect to the pyruvate dehydrogenase complex? 1. Carbon dioxide is released simultaneously with reduction of FAD 2. Energy from breakdown of pyruvate is conserved by oxidation of a disulfide bond. 3. The carbon in the released Carbon dioxide is one of the three carbons in pyruvate. 4. A disulfide bond is reduced simultaneously with reduction of FAD. 12) Which of the following is most correct with respect to the water produced by the electron transport chain? 1. This step is blocked by the binding of rotenone to the enzyme which catalyzes the reaction which produces water. 2. The Oxygen in the newly produced water comes from the Oxygen in Oxygen gas. 3. Water is produced at the step in the electron transport chain where NADH is oxidized. 4. The chemiosmotic hypothesis directly explains how water is produced. 5. Water is used by the electron transport chain, not produced. 13) Which of the following is most correct with respect to the glycerol-phosphate shuttle? 1. Used to make Glucose-1-phosphate from Glycogen. 2. Found only in C4 photosynthesis 3. Requires Acetyl-CoA. 4. Used to make glycerol-based phospholipids 5. Glycerol-3-phosphate moves across the inner membrane, into the matrix of mitochondria, carrying much of the reducing power of NADH. 14) Which of the following does Calcium directly bind to, resulting in activation of human skeletal muscle? 1. Troponin 2. Tropomyosin 3. alpha-Actinin 4. Myosin 15) Rigor is the result of? 1. very high Calcium concentrations in the myofibril interior. 2. lactate produced by fermentation in the muscle. 3. very low ATP concentrations in the myofibril interior. 4. overstimulation by the nerve. 5. eating too much oatmeal for breakfast. 16) Which of the following is most accurate concerning chlorophyll? 1. a protein 2. absorbs light in the green region of the spectrum 3. found only in autotrophs 4. None of answers 1, 2, or 3 are correct. 5. All of answers 1, 2, or 3 are correct. 17) A SRP (signal recognition particle) is associated most closely with 1. rough endoplasmic reticulum 2. smooth endoplasmic reticulum 3. Golgi 4. lysosomes 18) Which of the following structures is most closely associated with detoxification of barbiturates? 1. rough endoplasmic reticulum 2. smooth endoplasmic reticulum 3. Golgi 4. lysosomes 19) Which of the following structures did Cajal first associate with mucus producing cells which line the human intestinal epithelium? 1. rough endoplasmic reticulum 2. smooth endoplasmic reticulum 3. Golgi 4. lysosomes 20) Which of the following structures is most closely associated with protein synthesis. 1. rough endoplasmic reticulum 2. smooth endoplasmic reticulum 3. Golgi 4. lysosomes 21) Materials move between the endoplasmic reticulum and the Golgi by: 1. thermal diffusion of non-lysosomal vesicles 2. by lysosomes carrying the materials. 3. 4. by interconnections between the cisternae of the endoplasmic reticulum and the cisternae of the Golgi. ATP powered movement of non-lysosomal vesicles. 5. Materials don't move between the endoplasmic reticulum and the Golgi 22) True or false: Release of myosin from actin speeds up the release of ADP and phosphate from myosin by about 200 times. 1. True 2. False 23) Which of the following is most closely associated with the enzyme which catalyzes the reaction ADP + Creatine phosphate --> ATP + Creatine? 1. cisternae of the sarcoplasmic reticulum. 2. Z-line. 3. T-tubule. 4. I-band. 5. M-line 24) Which of the following does not shorten as the muscle contracts? 1. sarcomere length. 2. A-band. 3. I-band. 4. All of answers 1, 2, and 3 are equally correct. 25) True or false: Myosin does not obey Michaelis-Menten kinetics because it is an allosteric enzyme. 1. True 2. False 26) Suppose that phosphate (-2) is the only ion permeable through a membrane. If the membrane potential is -116mv and the internal concentration of phosphate is 0.01 mM, what is the external concentration of phosphate? 1. 0.0001 mM 2. 0.01 mM 3. 1 mM 4. 100 mM 5. 10000 mM 27) Suppose that sodium (+1) is the only ion permeable through a membrane. If the concentration of sodium inside the cell and external to it are both 10 mM, what is the membrane potential? 1. -58mV 2. +58mV 3. zero 4. -116mV 5. +116mV 28) Suppose that in a cell with normal membrane permeabilities, concentration of potassium inside the cell is 10 mM and outside is 100 mM. If concentration of chloride inside the cell is 100 mM, what is the concentration of chloride outside the cell? 1. 10 mM 2. 100 mM 3. 1M 4. 10 M 5. 0.1 mM 29) Suppose that some mystery ion is the only ion permeable through a cell's plasma membrane. If the membrane potential is +29 mV, concentration of the mystery ion inside the cell is 100 mM, and concentration of the mystery ion outside the cell is 10mM, what is the charge on the ion? 1. +1 2. -1 3. -2 4. +2 30) True or False: The action potential is a good example of the electrotonic spread of depolarization 1. True 2. False 31) Assume a normal nerve cell. Suppose you are able to experimentally manipulate membrane permeabilities. You instantaneously increase the sodium permeability so that it is 1000 times the membrane permeability to any other ion. Which of the following is most accurate? 1. The membrane potential changes rapidly from about -58 mV to about +58 mV with little ion movement. 2. The membrane potential changes rapidly from about +58 mV to about -58 mV with little ion movement. 3. The membrane potential changes slowly from about -58 mV to about +58 mV as large numbers of sodium ions enter the cell. 4. The membrane potential changes slowly from about +58 mV to about -58 mV as large numbers of sodium ions enter the cell. 32) Which of the following is a member of the myosin superfamily which acts in conjunction with microtubules? 1. kinesin 2. clathrin 3. spectrin 4. myosin 5. flagellin 33) Which of the following is a member of the myosin superfamily which acts in conjunction with microfilaments? 1. kinesin 2. clathrin 3. spectrin 4. myosin 5. flagellin 34) Which of the following is a major structural component of prokaryotic flagella? 1. myosin 2. flagellin 3. kinesin 4. tubulin 5. spectrin 35) A contractile ring would be associated with which of the following? 1. chromosome movement 2. movement of vesicles along microtubules 3. eukaryotic flagella 4. smooth muscle contraction 5. cytokinesis 36) A "9+2 structure" would be associated with which of the following? 1. chromosome movement 2. movement of vesicles along microtubules 3. eukaryotic flagella 4. smooth muscle contraction 5. cytokinesis 37) True or false: Prokaryotic cilia and flagella do not use ATP as an energy source. 1. True 2. False 38) Which of the following is most accurate with respect to permeability changes during an "action potential"? 1. Sodium permeability increases momentarily but potassium permeability remains unchanged. 2. Potassium permeability increases momentarily but sodium permeability remains unchanged. 3. Calcium permeability never changes, in any type of nerve. 4. Potassium permeability increases first, then sodium permeability increases. 5. Sodium permeability increases first, then potassium permeability increases. 39) Where would you most likely find myelin? 1. in the rough endoplasmic reticulum 2. around vertebrate nerve axons 3. in a thylakoid 4. in the matrix of mitochondria 40) Suppose that in some unusual cell, the only two ions permeable through the cell membrane are potassium and sodium. These two ions are equally permeable. Concentration of potassium inside the cell is 10 mM and outside is 100 mM. If concentration of sodium inside the cell is 100 mM, what is the concentration of sodium outside the cell? 1. 10 mM 2. 100 mM 3. 1M 4. 10 M 5. 0.1 mM 41) Suppose that in some unusual cell, the only two ions permeable through the cell membrane are potassium and calcium (+2). These two ions are equally permeable. Concentration of potassium inside the cell is 1 mM and outside is 10 mM. If concentration of calcium inside the cell is 1 mM, what is the concentration of calcium outside the cell? 1. 10 mM 2. 100 mM 3. 1M 4. 10 M 5. 0.1 mM 42) Where does cyanide have an effect upon metabolism? 1. By blocking transfer of electrons from NADH to the electron transport chain. 2. By blocking breakdown of pyruvate. 3. At the last step of the electron transport chain 4. By blocking protein synthesis and thus stopping the production of enzymes. 43) What is the adaptive value of the C4 photosynthetic pathway? 1. Allows plants to place the light-independent reactions away from locations that are high in oxygen. 2. Replacing the Calvin-Benson cycle with the C4 cycle is more efficient in cold climates. 3. Light-dependent reactions produce NADPH in C4, which is more efficient that producing NADH, as in C3 plants. 4. C4 plants use a chlorophyll which absorbs strongly in the green region of the spectrum. 44) Where is the electron transport chain located? 1. matrix of mitochondria 2. inner membrane of mitochondria 3. thylakoid membranes 4. stroma of chloroplast 45) Where are the light dependent reactions of photosynthesis located? 1. matrix of mitochondria 2. inner membrane of mitochondria 3. thylakoid membranes 4. stroma of chloroplast 46) Where are the light independent reactions of photosynthesis located? 1. matrix of mitochondria 2. inner membrane of mitochondria 3. thylakoid membranes 4. stroma of chloroplast 47) Where are is the TCA cycle located? 1. matrix of mitochondria 2. inner membrane of mitochondria 3. thylakoid membranes 4. stroma of chloroplast 48) Where are is the Calvin-Benson cycle located? 1. matrix of mitochondria 2. inner membrane of mitochondria 3. thylakoid membranes 4. stroma of chloroplast 49) True or false: Prokaryotic cells have a TCA cycle. 1. True 2. False 50) True or false: Plant cells do heterotrophic metabolism with release of Carbon dioxide, just as animal cells do. 1. True 2. False Press to SUBMIT or CLEAR to redo the exam Examination 1 Biology 255 - Fall 1994 - Dr. Thomas J. Herbert 1) Helical protein with 3.3 amino acids per helical turn. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 2) Protein with approximately 67% proline and 33% glycine. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 3) Protein with beta pleated sheet structure. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 4) Helical protein with 3.6 amino acids per helical turn. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 5) Not a protein. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 6) The major structural protein in hair. 1. silk 2. keratin 3. RNAase 4. collagen 5. porphyrin 7) The smallest prokaryotic cells now in existence. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 8) Autotrophs are among the cells found in this group or these groups. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 9) Cells of this type are eukaryotes. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 10) The smallest of this type of cell is about 0.05 micrometers in diameter. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 11) Lethal Yellowing is a disease caused by an organism from this group. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 12) It is thought that the first photosynthetic organisms were members of this group. 1. mycoplasm 2. bacteria only 3. human liver cells, 4. blue-green algae only 5. bacteria and blue green algae. 13) Michaelis-Menten data plotted as reaction velocity (V) vs substrate concentration (S). 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 14) Michaelis-Menten data plotted on a Lineweaver-Burke plot. 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 15) Reaction velocity vs substrate concentration for an allosteric enzyme. 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 16) Michaelis-Menten data plotted as 1/V vs. 1/S. 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 17) Percent oxygen saturation vs. partial pressure of oxygen for myoglobin. 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 18) Percent oxygen saturation vs. partial pressure of oxygen for hemoglobin.. 1. non-rectangular hyperbola 2. sigmoid (S-shaped) 3. linear (straight line), 4. exponential 5. rectangular hyperbola. 19) Bonds between water molecules in liquid water. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 20) Bonds between the oxidized residual groups of two cystine/cysteines. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 21) The peptide bond. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 22) Bonds between residual groups (except cystine/cysteine) in the interior of a globular protein. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 23) Bonds which hold each of the four hemoglobin subnits to each other. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 24) Bonds between molecules in pure liquid oil or gasoline. 1. hydrogen bond 2. disulfide bond 3. non-disulfide covalent bond 4. hydrophobic bond 5. ionic bond. 25) An allosteric enzyme. 1. CTP 2. myoglobin 3. aspartate transcarbamoylase 4. hemoglobin 5. ATP. 26) An inhibitor for aspartate transcarbamoylase. 1. CTP 2. myoglobin 3. hemoglobin 4. ATP. 27) An activator for aspartate transcarbamoylase. 1. CTP 2. myoglobin 3. hemoglobin 4. ATP. 28) A single subunit protein which is not an enzyme. 1. CTP 2. myoglobin 3. ATCase, 4. hemoglobin 5. ATP. 29) A multisubunit protein which is not an enzyme. 1. CTP 2. myoglobin 3. ATCase, 4. hemoglobin 5. ATP. Questions 30-33 use the following information: The following is a plot of reaction velocity V vs. substrate concentration S for a biochemical reaction catalyzed by a enzyme. Shown are the plots for the reaction in the absence of inhibitor (ºNORMALº) and in the presence of inhibitor (º + INHIBITORº). 30) Which of the following best describes the inhibitor? 1. competitive inhibitor 2. non-competitive inhibitor, 3. the ªinhibitorº is not really an inhibitor - it is actually an activator. 31) Which of the following best describes the enzyme? 1. allosteric with positive cooperativity 2. obeys Michaelis-Menten kinetics, 3. There is equal probability that the enzyme is allosteric with positive cooperativity or obeys Michaelis-Menten kinetics. 32) As you can see in the figure above, the velocity increases with increasing substrate concentration until it approaches a maximum - Vmax. If, in the absence of any inhibitor, if V = Vmax/2, what is the value of S? 1. Km/4 2. Km/3 3. Km/2 4. Km 33) As you can see in the figure above, the velocity increases with increasing substrate concentration until it approaches a maximum - Vmax. If, in the absence of any inhibitor, if V = Vmax/3, what is the value of S? 1. Km/4 2. Km/3 3. Km/2 4. 2Km 34) A substrate for alcohol dehydrogenase. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 35) Associated with the Bohr effect. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 36) A powerful reducing agent. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 37) Commonly used to disrupt hydrophobic bonds in proteins. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 38) Found naturally in skeletal muscle. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 39) Smells very bad - You must be especially careful not to spill this in a laboratory. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 40) Found naturally contained within red blood cells. 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 41) A major component of automobile coolant (antifreeze). 1. myoglobin 2. ethylene glycol 3. mercaptoethanol, 4. urea 5. hemoglobin. 42) Can be used to measure the Svedberg constant. 1. Sedimentation velocity ultracentrifugation, 2. Near-field optical microscopy, 3. Conventional, visible light microscopy, 4. X-ray diffraction, 5. SDS polyacrylamide gel electrophoresis. 43) Can observe details in structure as small as a few nanometers. 1. Sedimentation velocity ultracentrifugation, 2. Near-field optical microscopy, 3. Conventional, visible light microscopy, 4. X-ray diffraction, 5. SDS polyacrylamide gel electrophoresis. 44) Can be used to measure molecular weight. 1. Sedimentation velocity ultracentrifugation, 2. Near-field optical microscopy, 3. Conventional, visible light microscopy, 4. X-ray diffraction, 5. SDS polyacrylamide gel electrophoresis. 45) Is limited in resolution by the wavelength of visible light. 1. Sedimentation velocity ultracentrifugation, 2. Near-field optical microscopy, 3. Conventional, visible light microscopy, 4. X-ray diffraction, 5. SDS polyacrylamide gel electrophoresis. 46) The results of the use of this technique are often given in units of 10-13 sec. 1. Sedimentation velocity ultracentrifugation, 2. Near-field optical microscopy, 3. Conventional, visible light microscopy, 4. X-ray diffraction, 5. SDS polyacrylamide gel electrophoresis. Questions 47-48 use the following information: The following is a plot which shows the relationship between reaction velocity V and substrate concentration [S] for an enzyme catalyzed reaction. (Assume that all conditions for the validity of such a plot have been met.) 47) What is the value for Vmax? 1. 1 mM/sec 2. 0.4 mM/sec 3. 2.5 mM/sec, 4. Can't be determined from this graph without additional information. 48) What is the value for Km? 1. 1 mM 2. 0.4 mM 3. 2.5 mM, 4. Can't be determined from this graph without additional information. 49) When an enzyme is added to a biochemical reaction, which of the following would be expected to change for the reaction? 1. forward rate constant, 2. reverse rate constant / forward rate constant, 3. equilibrium constant, 4. final concentrations of reactants or products 5. all of 1, 2, 3 and 4 change. 50) A molecular chaperone is most closely related to which of the following processes? 1. Oxygen binding and release in the blood. 2. Competitive inhibition 3. Allosteric enzymes 4. Protein folding 5. The endosymbiont hypothesis Press to SUBMIT or CLEAR to redo the exam Examination 2 Biology 255 - Fall 1994 - Dr. Thomas J. Herbert 1) An intracellular "second messenger" associated with binding of the hormone angiotensin. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 2) Acts on the membrane of the endoplasmic reticulum to release Calcium. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 3) An intracellular "second messenger" associated with binding of the hormone glucagon. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 4) An intracellular "second messenger" associated with binding of the hormone norepinephrine. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 5) A neurotransmitter used in the central nervous system. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 6) A neurotransmitter antagonized by LSD. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 7) This hormone causes increased synthesis of glycogen in the liver. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 8) This hormone causes decreased synthesis of glycogen in the liver. 1. serotonin 2. Inositol-P3 3. insulin 4. cAMP 5. epinephrine 9) Very low permeability through resting cell membranes. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 10) High permeability through resting cell membranes. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 11) Permabilities of this ion or these ions increase significantly during the course of the action potential. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 12) The positive afterpotential is caused by increased permability for this ion or these ions. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 13) This ion or these ions is or are found in frog blood plasma at approximately 10 mM or less. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl14) This ion or these ions is or are found in the interior of frog muscle cells at approximately 10 mM or less. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and Cl- 5. Both K+ and Cl15) The Nernst potential of this ion or these ions is approximately +58mV for most cells. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 16) The Nernst potential of this ion or these ions is approximately -58mV for most cells. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 17) Three of these ions are actively transported across a cell membrane from the cell interior to the outside for each ATP used. 1. Na+ only 2. K+ only 3. Cl- only 4. Both Na+ and K+ 5. Both K+ and Cl 18) Glucose movement across the mucosal side of human intestinal epithelium and into the epithelial cell. 1. diffusion (Fick's law or facilitated) with cotransport of Na+ 2. diffusion (Fick's law or facilitated) without cotransport 3. active transport by a P-type pump 4. active transport by a V-type pump 5. diffusion (Fick's law or facilitated) with cotransport of K+ 19) Potassium movement from inside to outside of cells. 1. diffusion (Fick's law or facilitated) with cotransport of Na+ 2. diffusion (Fick's law or facilitated) without cotransport 3. active transport by a P-type pump 4. active transport by a V-type pump 5. diffusion (Fick's law or facilitated) with cotransport of K+ 20) Sodium movement from inside to outside of cells. 1. diffusion (Fick's law or facilitated) with cotransport of Na+ 2. diffusion (Fick's law or facilitated) without cotransport 3. active transport by a P-type pump 4. active transport by a V-type pump 5. diffusion (Fick's law or facilitated) with cotransport of K+ 21) Chloride movement from outside to inside of cells. 1. diffusion (Fick's law or facilitated) with cotransport of Na+ 2. diffusion (Fick's law or facilitated) without cotransport 3. active transport by a P-type pump 4. active transport by a V-type pump 5. diffusion (Fick's law or facilitated) with cotransport of K+ 22) Sodium movement fromoutside to inside of cells. 1. diffusion (Fick's law or facilitated) with cotransport of Na+ 2. diffusion (Fick's law or facilitated) without cotransport 3. active transport by a P-type pump 4. active transport by a V-type pump 5. diffusion (Fick's law or facilitated) with cotransport of K+ 23) The most important site in the human body for storage of glucose as a polymer of glucose units called starch. 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 24) Synthesizes enzymes which catalyze the release of glucose from cellulose. 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 25) MSG (monosodium glutamate) has a significant effect on the chemistry of this tissue. 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 26) Can perform fermentation to produce lactate (lactic acid). 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 27) The most important site in the human body for storage of glucose as a polymer of glucose units called glycogen. 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 28) Can perform fermentation to produce ethanol. 1. human liver 2. human stomach 3. human brain 4. human skeletal muscle cells 5. none of 1, 2, 3, or 4 are correct answers 29) When this molecule goes from the oxidized to the reduced state, it releases 2ATPs worth of energy. 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 30) This molecule is a nucleoside triphosphate which phosphorylates glucose-1-phosphate when glucose-1-phosphate is stored as a polymer in the human liver. 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 31) This molecule is used as a substrate for adenylate cyclase. 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 32) Two of these molecules are produced for each glucose used in glycolysis and used up during fermentation. 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 33) In glycolysis, this molecule donates a phosphate group to fructose-1-phosphate to produce fructose-1,6- diphosphate. 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 34) In glycolysis, the reaction which produces fructose-1,6-diphosphate uses this molecule as a positive allosteric effector (activator). 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 35) In glycolysis, the reaction which produces fructose-1,6- diphosphate uses this molecule as a negative allosteric effector (inhibitor). 1. FADH2 2. UTP 3. ATP 4. NADH 5. none of 1, 2, 3, or 4 are correct answers 36) An intrinsic membrane protein. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 37) An extrinsic membrane protein which sits on the inside surface of cell membranes. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 38) Identifies red blood cells as being in M or N blood groups. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 39) Identifies red blood cells as being in A, B, AB, or O blood groups. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 40) A phospholipid. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 41) A small membrane lipid which fills in the spaces between phospholipid molecules. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 42) Has a glycerol backbone with two hydrocarbon chains. 1. lecithin 2. cholesterol 3. glycophorin 4. glycolipid 5. spectrin 43) Associated with a depolarizing potential of 5-10 mV. 1. EPSP 2. IPSP 3. node of Ranvier 4. both answers 1 and 2 are equally correct 44) Associated with saltatory conduction. 1. EPSP 2. IPSP 3. node of Ranvier 4. both answers 1 and 2 are equally correct 45) Associated with electrotonic spread of membrane potential. 1. EPSP 2. IPSP 3. node of Ranvier 4. both answers 1 and 2 are equally correct 46) Associated with a hyperpolarizing potential of 5-10 mV. 1. EPSP 2. IPSP 3. node of Ranvier 4. both answers 1 and 2 are equally correct 47) Which of the following would be a likely consequence if the Sodium/Potassium pump ceased functioning in all the cells of your liver? 1. The liver would shrink. 2. There would be no more action potentials on the liver cells. 3. Serotonin would no longer be released by the liver cells. 4. Sodium would stop being actively transported into the liver cells. 5. The membrane potential across the liver cell membranes would change. 48) You are doing an experiment on the movement of some new molecule, "X", across cell membranes. You observe that net movement of "X" is always from regions of high concentration to regions of low concentration. The following is a table of flux (rate of movement per square micron of membrane area) vs. concentration of "X" outside the cell (Cout). What is the mechanism for movment? flux Cout (mM/sec-mm^2) (mM) -------------5 20 10 35 15 50 20 65 1. active transport 2. facilitated diffusion 3. fick's law (simple thermal) diffusion. 4. either answers b or c are equally correct. 5. any of answers 1, 2, or 3 are equally correct. 49) You land on a distant planet and find that cells on that plant have only one ion - Calcium, which is permeable across cell membranes. Calcium concentrations are: [Ca +2]inside =100 mM and [Ca +2]outside = 0.1 mM. What is the potential across the membrane (inside)? 1. +29 mV 2. -58 mV 3. +58 mV 4. -87 mV 5. -174 mV. 50) Suppose that Chloride and Potassium are equally permeable through cell membranes and no other ions are permeable. Given the following concentrations, [Cl -]inside =100 mM, [Cl -]outside = 1mM, [K +]outside = 100mM, what is [K +]inside? (HINT: Remember that there can only be one membrane potential across a membrane.) 1. 0.1 mM 2. 1 mM 3. 10 mM 4. 100 mM 5. 1000 mM Press to SUBMIT or CLEAR to redo the exam Examination 3 Biology 255 - Fall 1994 - Dr. Thomas J. Herbert 1) Motion of eukaryotic cilia and flagella 1. involves a "motor" near the cell surface 2. appears not to require ATP 3. requires energy input along their entire length 4. none of answers 1, 2 or 3 is correct. 2) Which of the following is an oxygen binding protein found in muscle ? 1. creatine phosphatase 2. tubulin 3. dynein 4. tropomyosin 5. myoglobin 3) Concerning microtubules: 1. form the core of the thick filaments of striated muscle 2. require globular actin for their formation 3. found in eukaryotic flagella 4. tubulin, of which they are made, hydrolyzes ATP to release energy for contractile activity. 5. none of the above are correct. 4) Which of the following regions of frog striated skeletal muscle is most closely associated with the dephosphorylation of creatine phosphate ? 1. sarcoplasmic reticulum, 2. M-line, 3. troponin, 4. tropomyosin, 5. Z-line 5) Which of the following molecules is responsible for binding Ca+2 and activating the interaction between actin and myosin during contraction of frog striated muscle ? 1. myosin 2. actin 3. tropomyosin 4. troponin 5. tubulin. 6) Which of the following states of muscle is characterized by very low concentrations (near zero) of ATP ? 1. relaxed 2. California 3. active contraction 4. rigor 5. twitch 7) Approximately, what is the minimum concentration of free calcium required for activation of muscle contraction ? 1. 10-6M 2. 10-16M 3. 10-8M 4. 10-3M 5. 10-1M. 8) Approximately, what is the normal concentration of free calcium adjacent to the thick filaments while a muscle is at rest ? 1. 10-6M 2. 10-16M 3. 10-8M 4. 10-3M 5. 10-1M. 9) The enzymatic properties of myosin reside in the portion known as 1. LMM 2. TM 3. TN-T 4. RER 5. HMM 10) In skeletal, striated, muscle found in ALL species of vertebrates, calcium causes activation of muscle by binding to a protein associated 1. only with the thin filaments. 2. only with the thick filaments. 3. 4. in some species of animals, the thick filaments and in some the thin filaments, but never both in the same animal. in some species of animals, the thick filaments, in other species, the thin filaments, and in some species, both the thick and the thin filaments. 11) In photosystem II, the electrons which will be transferred from the excited state of chlorophyll through a series of steps to plastoquinone (pQ) are initially obtained from: 1. water 2. oxygen 3. ribulose-1,5 bisphosphate 4. NADPH 5. carbon dioxide 12) Kranz anatomy is usually associated with plants which 1. 2. live in very cool, moist places have a curious reaction scheme which stores carbon dioxide by combining it with ribulose to form pyruvate. 3. have a developed mesophyll which closely surrounds the bundle sheath cells. 4. have only the Calvin-Benson cycle. 5. have strangely developed mitochondria 13) Which of the following regions of frog striated skeletal muscle contain NO myosin ? 1. H-zone 2. M-line 3. I-band 4. A-band 14) Which of the following best represents the color(s) absorbed by a solution of chlorophyll: 1. green only 2. red and green 3. green and blue 4. blue and red 5. red only 15) Identify the system mostly closely associated with detoxification of barbituates? 1. Cytoplasmic, soluble ribosomes. 2. Rough Endoplasmic Reticulum. 3. Smooth Endoplasmic Reticulum. 4. Lohman Reactions. 5. Sarcoplasmic Reticulum. 16) Identify the system mostly closely associated with manufacture of proteins destined to be secreted from cells? 1. Cytoplasmic, soluble ribosomes. 2. Rough Endoplasmic Reticulum. 3. Smooth Endoplasmic Reticulum. 4. Lohman Reactions. 5. Sarcoplasmic Reticulum. 17) Where would you likely find reactions which use a mechanism described by the chemiosmotic hypothesis? 1. only mitochondria 2. only chloroplasts 3. only sarcoplasmic reticulum 4. both mitochondria and chloroplasts 5. both mitochondria and sarcoplasmic reticulum. 18) The light-dependent reactions of photosynthesis directly produce: 1. NADH 2. NADPH 3. glyceraldehyde-3-phosphate 4. water 19) Which of the following attaches thin filaments of smooth muscle to membrane proteins? 1. creatine 2. myosin 3. tropomyosin 4. troponin 5. alpha-actinin 20) Which of the following has the higher numerical pH (more alkalinans:? 1. the space between the inner and outer membrane of mitochondria. 2. the matrix of the mitochondria. 3. both the matrix and the intermembrane space have the same pH. 21) True or False: "In eukaryotic autotrophs, there is no Krebs' cycle. " 1. True 2. False 22) Dr. Krebs is giving a lecture and claims that NADH produced in glycolysis moves easily into the mitochondria. What is wrong with this statement? 1. 2. 3. 4. NADPH is produced by glycolysis, not NADH. NADH does not move into the mitochondria. Instead, reducing power moves from the cytoplasm into the mitochondria in the form of dihydroxyacetone phosphate. No NADH is produced in glycolysis. NADH does not move into the mitochondria. Instead, reducing power moves from the cytoplasm into the mitochondria in the form of glycerol-3-phosphate. 5. Actually, Dr. Krebs is correct - There is nothing wrong with his statement! 23) In the pyruvate dehydrogenase complex associated with the entry of pyruvate into the Krebs cycle, which of the following is correct? 1. An acetyl fragment is temporally bound to a reduced sulfide group to give an oxidized sulfide group with the acetyl fragment attached. 2. The carbon in the carbon dioxide which is released is a carbon which was one of the four carbons in pyruvic acid (pyruvatans:. 3. The acetyl CoA produced then releases the acetyl fragment which binds to citric acid, a four carbon molecule, to produce oxaloacetic acid, a five carbon molecule. 4. None of answers 1, 2, or 3 are correct. 5. All of answers 1, 2, or 3 are correct. 24) Where would we find a "signal peptide", a 15 to 20 amino acid hydrophobic amino acid sequence? 1. At the beginning of proteins manufactured for export from a cell. 2. On the HMM portion of myosin. 3. At the beginning of proteins manufactured for use in the cytoplasm. 4. As part of a molecule that binds alpha-actinin to membrane proteins. 5. none of the above answers are correct. 25) The Z disks of myofibrils of striated, skeletal muscle have which of the following proteins ONLY along the periphery and NOT in the interior where the thin filaments attach? 1. creatine phosphokinase 2. desmin 3. tropomyosin 4. troponin 5. alpha-actinin. 26) True or False: "Eukaryotic autotrophs have mitochondria and the reactions of the Krebs cycle and electron transport chain, just as eukaryotic heterotrophs do." 1. True 2. False 27) True or False: "In C4 plants, there is no Calvin-Benson (C4) cycle." 1. True 2. False 28) Which of the following is true with respect to manufacture of insulin? 1. manufactured on the smooth endoplasmic reticulum of pancreatic beta cells. 2. manufactured by ribosomes which are not attached to endoplasmic reticulum. 3. manufactured on the rough endoplasmic reticulum of liver cells. 4. manufactured on the smooth endoplasmic reticulum of liver cells. 5. none of the above answers are correct. 29) Which of the following regions of frog striated skeletal muscle contain both actin and myosin ? 1. H-zone 2. M-line 3. I-band 4. A-band 5. Z-line 30) Which of the following is most closely associated with producing the force which results in normal cleavage of all animal cells which divide? 1. colchicine 2. axostyles 3. spindle fibers 4. microfilaments. 31) Which of the following is most closely associated with producing the force which results in normal chromosome movement in animal cells which divide? 1. colchicine 2. axostyles 3. spindle fibers 4. microfilaments. 32) Which of the following is the best description of the adaptive value of C4 photosynthesis. 1. Is more efficient than C3 photosynthesis. 2. Works better in cool, wet habitats than C3 photosynthesis. 3. Permits the plant to absorb more of the visible light spectrum. 4. Reduces photorespiration. 33) True or False: "In prokaryotic autotrophs, there is no Krebs' cycle. " 1. True 2. False 34) A five carbon carbohydrate found in the Calvin-Bensen cycle 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 35) A four carbon molecule involved in the Hatch-Slack (C4) pathway. 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 36) A metabolic poison which inhibits one of the reactions in the Krebs'cycle and thus causes failure of aerobic metabolism. 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 37) A very small ion, consisting of only one carbon and one nitrogen. 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 38) A normal component of the electron transport chain 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 39) An enzyme associated associated with the light-independent reactions of photosynthesis. 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers 40) The green pigment which absorbs light energy for photosynthesis in most autotrophs. 1. cytochrome 2. cyanide 3. ribulose-1-5-bisphosphatase 4. malate 5. choose this answer if none of 1, 2, 3 or 4 are correct answers Press to SUBMIT or CLEAR to redo the exam Bil 255, Cell Biology - Final Examination - 5 August, 1994 Choose the best or most complete and accurate answer. Unless otherwise stated for membrane potentials, temperature equals 18 degrees C. (Ca++)o indicates the concentration of Calcium outside the cell, (Ca++)i, the concentration of Calcium inside the cell, etc. 1) Motion of prokaryotic cilia and flagella 1. appears not to require ATP 2. requires free energy input along their entire length 3. depends on myosin 4. is none of the above. 2) Which of the following region of frog striated skeletal muscle best defines the region of the myofibril which contains most of the enzyme which catalyzes the reaction of creatine phosphate and ADP to form creatine and ATP ? 1. H-zone, 2. M-line, 3. I-band, 4. A-band, 5. Z-line 3) Which of the following is closest to the ratio of potassium permeability to sodium permeability (PK/PNa across a typical resting muscle cell membrane at rest? 1. 1000.00, 2. 0.01, 3. 1.00, 4. 10.00, 5. 100.00 4) A typical value for the sodium Nernst potential of a squid giant axon is 1. +60mv., 2. -60mv. 3. -200mv., 4. about zero 5. +200mv. 5) Which of the following is the immunoglobulin most closely associated with allergy/hypersensitivity reactions ? 1. IgM, 2. IgD 3. IgE 4. IgG 5. IgA 6) Which of the following is the most significant immunoglobulin associated with the defense of mucous membranes of the nose, mouth and throat ? 1. IgA 2. IgD 3. IgE 4. IgG 5. IgM 7) Which of the following is the immunoglobulin with the highest molecular weight ? 1. IgA 2. IgM 3. IgE 4. IgG 5. IgD 8) In humans, which of the following structures is most responsible for processing and maturation of lymphocytes associated with the humoral immune system ? 1. Thymus 2. Bursa of Fabricus, 3. Bone Marrow, 4. Kidney 5. The Mast. 9) Which of the following is the excitatory transmitter found in mammalian skeletal neuromuscular junctions ? 1. glutamate 2. acetylcholine 3. ribulose 4. serotonin 5. LSD. 10) Suppose that cell membranes of a particular cell are permeable only to iron (Fe+3). If external iron concentration, (Fe+3)o equals 0.001 mM and internal iron concentration, (Fe+3)i also equals 0.001 mM, what is the membrane potential, Vin ? 1. -58mV 2. +232mV, 3. 0 mV, 4. -232mV, 5. +58mV. 11) At the end of an action potential, the decrease of the membrane potential to a value more negative than that of the resting potential is caused by: 1. electrotonic spread of current. 2. low values for gCl/gK (gCl, gK are conductances of Cl and K, respectively 3. high values for gCl/gK (gCl, gK are conductances of Cl and K, respectively) 4. the sodium conductance remaining unusually high relative to its value at rest. 5. the sodium conductance remaining unusually low relative to its value at rest. 12) Which of the following molecules is binds Ca+2 and thus is responsible for activating the interaction between actin and myosin during contraction of frog striated muscle ? 1. myosin, 2. actin, 3. tropomyosin, 4. troponin, 5. alpha-actinin. 13) Which of the following states of muscle is characterized by very low concentrations (near zero) of ATP ? 1. relaxed, 2. anarchy, 3. active contraction, 4. rigor, 5. twitch 14) Which of the following attaches thin filaments of smooth muscle to membrane proteins? 1. actin 2. myosin 3. tropomyosin 4. troponin 5. alpha-actinin 15) Which of the following is a protein which consists almost totally of helical secondary structure of 3.3 amino acids per helical turn ? 1. keratin 2. collagen 3. silk 4. two of answers 1-4 are correct. 5. myoglobin 16) The enzymatic properties of myosin reside in the portion known as 1. LMM, 2. TM, 3. TN-T, 4. LSD, 5. HMM 17) Assuming Michaelis-Menten kinetics, what is the effect of a noncompetitive inhibitor on enzyme catalyzed reactions as inhibitor concentration is decreased ? 1. The "effective" Km increases. 2. The "effective" Km decreases. 3. No change in "effective" Km but "effective" Vmax increases. 4. No change in "effective" Km but "effective" Vmax decreases. 5. Both "effective" Km and Vmax change. 18) Given that substrate concentration is kept constant, which of the following causes an increase in the velocity of a reaction catalyzed by asparate transcarbamoylase ? 1. LSD 2. CTP 3. ATP 4. two of answers 1-3. 5. all of answers 1-3. 19) On a graph showing reaction velocity V vs. substrate concentration [S] for an enzyme obeying Michaelis-Menten kinetics, at what value for [S] is V = Vmax/3 ? 1. [S] = -1/(3Km) 2. [S] = 1/(2Km) 3. [S] = Km/2 4. [S] = Km/3 5. [S] = -Km 20) The intra-chain bonds which are primarily responsible for formation and stabilization of the alpha-helical structure are: 1. hydrogen bonds 2. non-disulfide covalent bonds 3. ionic bonds 4. disulfide covalent bonds 5. hydrophobic bonds 21) For an enzyme obeying Michaelis-Menten kinetics, suppose the reaction velocity is 75% of maximum at a substrate concentration of 2mM. What is the value for Km, the Michaelis constant ? 1. 1.50 mM 2. 1.67 mM 3. 0.67 mM 4. 1.33 mM 5. 2.67 mM. 22) CAM metabolism has a mechanism which is most similar to 1. C4 metabolism 2. Calvin-Benson cycle 3. Krebs' cycle 4. Light-dependent reactions of photosynthesis 5. the reactions in the Golgi apparatus. 23) In which of the following molecules would you expect to find a porphyrin ring structure with an iron atom bound in the center of the ring? 1. ribonuclease 2. keratin 3. ATCase 4. myoglobin 5. not found in any of 1-4 24) Low numerical values for pH result in hemoglobin1. releasing CO2 2. binding additional oxygen 3. unwinding most of its alpha-helix 4. releasing bound oxygen 5. pH changes do not cause any of 1-4. 25) In photosystem II, the electrons which will be transferred from the excited state of chlorophyll to plastoquinone (pQ) are obtained from: 1. water 2. plastocyanine 3. ribulose-1,5 bisphosphate 4. NADPH 5. carbon dioxide 26) Kranz anatomy is usually associated with plants which 1. 2. live in very cool, moist places have a curious reaction scheme which stores carbon dioxide by combining it with ribulose-1,5, bisphosphate to form 3-phosphoglycerate. 3. have a developed mesophyll which closely surrounds the bundle sheath cells. 4. have only the Calvin-Benson cycle. 5. have strangely developed mitochondria 27) What is the thickness of a typical cell membrane? 1. 0.07 nm. 2. 70 nm. 3. 7 mm. 4. 7 mm. 5. 7 nm. 28) Concerning the "doublet tubules" and associated proteins of cilia and flagella 1. doublet tubules are connected to each other by actin 2. the "arms" are dynein, an ATPase 3. myosin is the chief protein of the doublet tubules. 4. the doublet tubules contract to produce motion 5. all of the above are correct 29) Which of the following best represents the color (s) absorbed by a solution of chlorophyll: 1. green only 2. red and green 3. green and blue 4. blue and red 5. red only 30) Which of the following molecules provides directly the free energy for the addition of Glucose-1-Phosphate units to Glycogen? 1. ATP 2. NADPH 3. NADH 4. GTP 5. UTP 31) True or False: "One of the reactions of glycolysis which will not go backwards (towards glucose in gluconeogenesis is phosphoenol pyruvate <-> pyruvate. In gluconeogenesis phosphoenol pyruvate is formed from pyruvate by a circuitous route which includes the movement of pyruvate into the mitochondria and conversion to oxaloacetate and malate." 1. True 2. False 32) Which of the following best identifies spectrin? 1. An intrinsic membrane glycoprotein. 2. A contractile protein closely related to myosin - Has ATPase activity. 3. A key intermediate in the electron transport chain in mitochondria 4. An external surface protein - binds cells together in the intestinal epithelium. 5. An internal surface protein - found in erythrocytes. 33) Your roommate has just swallowed a quantity of antifreeze solution containing almost 100% ethylene glycol. No physician is available and you wish to save that person's life - What should you do? 1. Administer oxalic acid to your roommate. 2. Administer ethanol to your roommate. 3. Administer methanol to your roommate. 4. Administer more ethylene glycol to your roommate. 5. Administer glycerol to your roommate. 34) Which of the following is a realistic structure for an amino acid side chain and would be most likely to participate in hydrophobic bonding between different regions of a protein chain? 1. -CH2-CH2-C00- 2. -(CH2)4-NH2 3. -CH2-OH 4. -CH2-CH2-PO4 5. -CH2-CH2-CH3 35) The presence of myelin around nerve axons: 1. Slows down conduction of action potentials. 2. Has no effect upon the speed of action potentials. 3. Speeds up conduction of action potentials. 4. Myelin is not found associated with the axons of any nerve cells. 36) With respect to the Golgi apparatus: 1. It is a microfilament based contractile organelle in wood roaches. 2. It contains many destructive enzymes and primarily attacks endocytosed materials. 3. Found only in plants with Kranz anatomy. 4. Stores calcium in striated muscle cells. 5. It is responsible for the conversion of proinsulin to insulin. 37) Identify the system mostly closely associated with detoxification of barbiturates? 1. Golgi. 2. Rough Endoplasmic Reticulum. 3. Smooth Endoplasmic Reticulum. 4. Lysosomes. 5. Schwann cells. 38) Identify the system mostly closely associated with manufacture of proteins destined to be secreted from cells? 1. Cytoplasmic, soluble ribosomes. 2. Rough Endoplasmic Reticulum. 3. Smooth Endoplasmic Reticulum. 4. Lysosomes. 5. Sarcoplasmic Reticulum. 39) With which of the following would you most likely find PIP2 associated? 1. Synaptic transmission. 2. The pyruvate dehydrogenase complex. 3. Movement of the free energy associated with NADH into the mitochondria. 4. The second messenger hypothesis. 5. Humoral immunity. 40) Which of the following most closely describes a protein which helps proteins fold up as they are manufactured by the ribosome? 1. Complement 2. G-protein 3. Chaperone 4. PIP2 5. IgG 41) Why is rough endoplasmic reticulum called "rough"? Choose the best answer: 1. Cytoplasmic surface is covered with protein. 2. Lysosome form as buds from its surface. 3. It is covered with ribosomes. 4. The surface as little hills and valleys where the membrane folds in and out. 42) Which of the following is true with respect to the sarcoplasmic reticulum? 1. Found in prokaryotes. 2. Adds carbohydrate to protein to make glycoproteins. 3. Is the site in muscle cells where Calcium is stored. 4. Both 2 and 3 are true, but 1 is not. 5. All of 1, 2, and 3 are true. 43) Which of the following is closely associated with "storage diseases"? 1. Lysosomes. 2. Golgi apparatus. 3. Smooth endoplasmic reticulum. 4. Rough endoplasmic reticulum. 44) Which of the following is closely associated with the disease asbestosis? 1. Lysosomes. 2. Golgi apparatus. 3. Smooth endoplasmic reticulum. 4. Rough endoplasmic reticulum. 45) Which are a major group of phagocytotic cells of the mammalian circulatory system? 1. Lysosomes. 2. Erythrocytes. 3. B-lymphocytes. 4. T-lymphocytes. 5. Macrophages. Press to SUBMIT or CLEAR to redo the exam ...
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This document was uploaded on 10/27/2011 for the course BIL 255 at University of Miami.

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