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exam1 - First Hourly Examination BISC 220 Spring 2008 15...

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Unformatted text preview: First Hourly Examination BISC 220 Spring 2008 , 15 February 2008 Name Kg \/ ID Number This examination has 9 pages and 44 questions. Be sure you have a complete examination. Please put your name and U30 ID number on the top of each page. Remember to use your time wisely during the examination period. The following 24 questions are worth 3 points each. 1. Altering which of the following levels of structural organization could change the function of a protein? a. quaternary d. tertiary b. primary @all of the above c. secondary ' 2. The hydrogenation of vegetable oil would result in which of the following? a. an inerease in the number of hydrogen atoms in the oil (fat) molecule b. a decrease in the number of carbonécarbon double bonds in the oil (fat) molecules c. the oil (fat) probably becoming a solid at room temperature d. A and C only a ' , B, and C 3. All of the following membrane activities require energy from ATP hydrolysis except .‘acilitated diffusion. d. translocation of potassium into a cell. b. active transport. e. N a+ ions moving out of the cell. c. proton pumps. 4. A molecule with the formula C18H3602 is probably a a. protein. d. nucleic acid. b. hydrocarbon. e. carbohydrate. ©1ipid~ 5. A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it a. would function only as a base because of the amino group. b. would function only as an acid because of the carboxyl group. c. would function as neither an acid nor a base. @would function as both an acid and a base. e. is impossible to determine h0w it would function. 6. The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via . a. gap junctions. d. plasmodesmata. b. DNA and RNA. @integrins. c. the nucleus. ~ Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR Ml MT NE NT PC RB RV Name lD Number 7. Which of the following is true when an ice cube cools a drink? .(metic energy in the drink decreases. b. Evaporation of the water in the drink increases. c. A calorie of heat energy is transferred from the ice to the water of the drink. (1. Molecule collisions in the drink increase. e. The specific heat of the water in the drink decreases. 8. According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids? a. They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. b. They are free to depart from the membrane and dissolve in the surrounding solution. . c. They have hydrophilic tails in the interior of the membrane. .‘hey can move laterally along the plane of the membrane. -“e. They frequently flip~flop from one side of the membrane to the other. 9. The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? a. 2.0°C b. 20.0°C ©10.0°C d. 02°C e. 1.0°C 10. Which of the following statements is comm about diffusion? 1 0'0 M a. It requires an expenditure of energy by the cell. b. It is very rapid over long distances. ®It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. "(1. .It is an active prOCess in which molecules move from a region of lower \_, concentration \’ . )f to one of Ill—g'ECI' concentration. 6. It requires integral proteins in the cell membrane. 11. Observe the structures of glucose and fructose in the figure to the right. These two molecules are a. nonisotopic isomers. b. geometric isotopes. tructural isomers. . geometric isomers. e. enantiomers. 12. Saturated fatty acids .ave a higher ratio of hydrogen to carbon than do unsaturated fatty acids. b. have double bonds between carbon atoms of the fatty acids. c. are the predominant fatty acid in corn oil. d. are usually produced by plants. e. are usually liquid at room temperature. Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR MI MT NE NT PC RB RV Name ID Number 13. If the pH of a solution is decreased from 9 to 8, it means that the a. concentration of OH” has increased 10 times what it was at pH 9. b. concentration of H+ has increased 10 times what it was at pH 9. c. concentration of H+ has decreased 10 times what it was at pH 9. d. concentration of OH' has decreased 10 times what it was at pH 9. and D are correct. 14. The figure to the right best illustrates the a. double helix structure of DNA. - b. primary structure of a polysaccharide. ©secondary structure of a polypeptide. d. tertiary structure of a polypeptide. e. quaternary structure of a protein. 15. Which of the following types of reactions would decrease the entropy within a cell? ‘@dehydration reactions d. respiration b. digestion e. catabolism c. hydrolysis 16. The selective permeability of biological membranes is dependent on which of theg o o . a. the lipid bilayer being permeable to primarily small, nonpolar molecules b. the type of transport proteins that are present in the membrane c. the types of carbohydrates on the surface of the membrane .A and B only e. A, B, and C 17. Humans can digest starch but not cellulose because a. humans harbor starch—digesting bacteria in the digestive tract. b. the monomer of starch is glucose, while the monomer of cellulose is galactose. c. the monomer of starch is glucose, while. the monomer of cellulose is maltose. d. humans have enzymes that can hydrolyze the beta ([3) glycosidic linkages of starch but not the alpha ((1) glycosidic linkages of cellulose. ‘umans have enzymes that can hydrolyze the alpha ((1) glycosidic linkages of starcy but not the beta ([3) glycosidic linkages of cellulose. 18. Which of the following statements is (are) true about the phosphate ion? a. It is negatively charged. @Only A and B are true. b. It has acid properties. e. A, B, and C are true. c. It is hydrophobic. Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR MI MT NE NT PC RB RV Name iD Number 19. A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 difi'erences from a rat, and 5 differences from a frog. These data suggest that the new organism @s more closely related to frogs than to humans. b. may have evolved from rats but not from humans and gibbons. ". c. may have evolved from gibbons but not rats. ‘ d. is more closely related to humans than to rats. e. is more closely related to humans than to frogs. 20. A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be comprised of ‘ a. 120 cytosine and 120 thymine molecules. b. 120 adenine and 120 uracil molecules. c. 240 guanine and 240 thymine molecules. d. 240 adenine and 240 cytosine molecules. .20 thymine and 120 adenine molecules. 21. A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in a lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively, a. mitochondria and chloroplasts. b. mitochondria and peroxisomes. c. peroxisomes and chloroplasts. i @hloroplasts and mitochondria. v e. chloroplasts and peroxisomes. 22. An example of a hydrogen bond is the bond between @the H of a water molecule and the N of another molecule. b. Na+ and or in salt. c. the two hydrogen atoms in a molecule of hydrogen gas (H7). d. C and H in methane (CH4). e. Mg+ and Cr in MgClz. 23. Which of the following is nata known function of the cytoskeleton? a. to maintain the characteristic shape of the cell b. to assist in cell motility by interacting with specialized motor proteins c. to hold mitochondria and other organelles in place within the cytosol d. to provide mechanical support to the cell maintain a critical limit on cell size Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR Mi MT NE NT PC RB RV Name ID Number 24. Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes? @a cell that is producing cytoplasmic enzymes b. a cell that is digesting food particles c. a cell that is constructing its cell wall or extracellular matrix d. a cell that is secreting proteins e. a cell that is enlarging its vacuole The following fl questions are worth 4 points each. 25. Based on the model of sucrose uptake presented in class (a sucrose-proton co-symport system), which of the following experimental treatments would immediately increase the rate of sucrose transport into the cell? i a. decreasing cytoplasmic pH b. decreasing extracellular sucrose concentration c. adding a substance that makes the membrane more permeable to hydrogen ions @decreasing extracellular pH e. adding an inhibitor that blocks the regeneration of ATP 26. Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell? (9 chemical reaction in which both the reactants and products are only used in a metabolic pathway that is completely inactive b. a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium c. a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings d. an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment e. There is no possibility of having chemical equilibrium in any living cell. 27. The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. Where are the corresponding reactions likely to occur in prokaryotic respiration? a. in the cytoplasm b. on the inner mitochondrial membrane c. on the endoplasmic reticulum @on the plasma membrane e. on the nuclear envelope Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR MI MT NE NT PC RB RV Name ID Number Side Side A Initial setup B 0.4M glucose 0.5M NaCl 0.8 M glucose 0.4M NaCl 28. The solutions in the arms of a U—tube (above) are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled With a solution of 0.4 M glucose and 0.5 M sodium chloride (N aCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the samelf you examine side A after 3 days, you should find ‘ a. a decrease in the concentration of NaCl, an increase in water level, and no change in Ct—hfoncentration of glucose. decrease in the concentration of NaCl and a decrease in the water level. c. no change in the concentration of NaCl and, glucose and an increase in the water level. (1. a decrease in the concentration of NaCl and glucose and an increase in the water level. 6. no net change in the system. 29. Which of the following statements about membrane structure and function IMG' 2“ a. Diffusion of gases is faster in air than across membranes. b. Diffusion, osmosis, and facilitated diffusion do not require any direct energy input from the cell. c. The types of proteins that are exposed on one side of a membrane are nearly 1 entical to those exposed on the other side of the membrane. d. Voltage across the membrane depends on an unequal distribution of ions across the plasma membrane. e. Special membrane proteins can cotransport two solutes by coupling diffusion down a concentration gradient to transport against the concentration gradient. 30. How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids? a. 412 b. 1220 c. 125 d. 20 .2012 Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR Mi MT NE NT PC RB RV Name ID Number 31. At which bond would water need to be added to achieve hydrolysis of the peptide (above) into its component amino acids? a.A b.B @c d.D e.E 32. Which of the following statements is not representative of the second law of thermo namics? ~ éivery energy transformation by a cell decreases the entropy of the universe. b. Heat represents a form of energy that cannot be used by most organisms to do work. c. Without an input of energy, organisms would tend towards increasing entropy. (1. Cells require a constant input of energy to maintain their high level of organization. e. Conversion of energy from one form to another is always accompanied by some lossof free energy. ‘ 33. The sodium—potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on? It will be on the cytoplasmic side of the ER. b. It will be on the side facing the interior of the ER. c. It could be facing in either direction because the orientation of proteins is @ scrambled in the Golgi apparatus. (1. It doesn't matter, because the pump is not active in the ER. e. Not enough information is provided to answer this question. 34. One of the buffers that contributes to pH stability in human blood is carbonic acid (HZCO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3) and a hydrogen ion (H+). Thus, I H2C03 <=> HCO3’ + H+ If the pH of the blood drops, one would expect a. the concentration of hydroxide ion (OH') to increase. @the PEG; to act as an acid and remove excessH+ with the formation of H2C03. c. a decrease in the concentration of HZCO3 and an increase in the concentration of HCO3'. d. the concentration of bicarbonate ion (HCO3‘) to increase. '.&e HCO3' to act as a base and remove excess H+ with the formation of H2C03. Please circle your TA's initials: AF AG JB JH JJ JM JS JV KR MI MT NE NT PC RB RV Name ID Number 35: Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon? a. the change in density when it condenses to form a liquid or solid b. the high surface tension of water . c. reactions with other atmospheric compounds d. the release of heat by the breaking of hydrogen bonds .the release of heat by the formation of hydrogen bonds 36. Most cells cannot harness heat to perform work because .emperature is usually uniform throughout a cell. b. heat can never be used to do work. c. cells do not have much heat; they are relatively cool. d. heat denatures enzymes. ' e. heat is not a form of energy. The following short answer questions are worth 5 points each. Please do not exceed the area of the boxes when they are supplied. Doing so will annoy the graders, with predicable consequences. 37. Circle each of the asymmetric carbon atoms in the structure below. cnzon ' {Jo/4' 0 H ‘ o ‘1‘ Ct, 38. Draw the enantiomer of the structure \1C’ totheright. l ’c .. H H—“T—on ”f’ I H .. C.“ ° HO—ac—H H : ‘I no - C " H H—C—DH ‘ I Ho" C'- ‘ H—SO I 0' Cuba H H—C-OH l 8 Name ID Number 39. What is the -h ~siolo;'c~a1 role of the structure limited b. the tono - last? ‘BQCtnestes flfirogevte 05 mas—h, gene/wrath b3; ‘HAQ ckgm F\O\gw\ 40. One strand of DNA has the nucleotide sequence 3’ ATGGCTGTAA 5’. Write the Please provide a definition for each of the following terms. These are worth 3 points each, and you should not exceed the size of the boxes here, either. 41. emerv ant Vrosyexx-Y 0? 0t CDuEC‘HOW 6; Obsecfls M \‘5 not Vgohd-odole Pvevvvfine, YVOPQfl-«g; GYPHAC Wldwicl o‘e . , \ 43. isoto e {Anemia VOW/x OVM’V Mwbeys 0F “Whons \vx We, modem . 44. h dronium ion ...
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