Test 1 Spring 2002

Test 1 Spring 2002 - Bil 255 - Cellular & Molecular...

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Unformatted text preview: Bil 255 - Cellular & Molecular Biology Dr. Charles Mallery Spring 2002 Test #1 – 2/21/02 FORM 0 DIRECTIONS: Choose the BEST answer from among the choice given. 01. While Matthais Schleiden and Theodor Schwann are credited with the Cell Theory, the statement “Every cell comes from a cell”, which is truly the foundation of the Cell Theory was made by? a) Rudolf Virchow b) Robert Hooke c) Antonie Leeuwenhoek d) J.D.Watson e) none of these 02. The first laboratory synthesis of a natural biological molecule (urea) which laid the foundation of the science of biochemistry was done in 1828 by? a) Erwin Chargaff b) Ed Buchner c) Calvin Bridges d) Frederich Wohler e) none of these 03. One of the first uses of radioisotopes in cell biology was that of 3 2P in proving that DNA is the genetic material. These experiments were done by? a) Avery, MacLeod, & McCarty b) Alfred Hershey & Martha Chase c) Erwin Chargaff d) Thomas Hunt Morgan e) none of these is correct 04. The first human cells grown in tissue culture were? a) E. coli cells b) giardia cells c) Hela cells d) embryonic stem cells e) none of these is correct 05. The direct exposure of photographic film by beta particles or gamma rays from radioisotopes incorporated into the molecules within cells that have been prepared for microscopy is known as? a) microspectrophotometry b) autoradiography c) nuclear magnetic resonance spectroscopy d) cytometry e) none of these is correct 06. Cells exhibit a continual flux of energy and matter supplied by the environment from which cells extract the factors necessary for self-support and development. Which of the following are mechanisms by which cells can extract energy from their environment? a) capture of light energy in photosynthesis b) cellular redox reactions c) H + ion pumps d) electron flow through carrier proteins e) choose this answer if all of these are mechanisms of energy capture 07. A new theory of evolution and the origin of life on Earth holds that life on Earth was seeded from space, possibly comets, which may have carried bacterial life across galaxies, and is referred to as the theory of? a) Special Creation b) Panspermia c) SETI d) Big Bang e) none of these is correct 08. The chemical evolution leading to cellular life on earth almost four billion years ago likely passed through a stage where RNA alone performed all of the functions of the modern macromolecules RNA, DNA and protein. a) true b) false 09. All cells metabolize and therefore most of the metabolic reactions that occur in cells are at equilibrium. a) true b) false 10. Cell metabolism might best be described as? a) random reactions which release the energy stored in carbon compounds b) a closed equilibrium system with no exchange of material or energy with the environment c) only endergonic reactions, which expend energy driving reactions d) reactions that use energy & material from the environment to synthesize cell components & do metabolic work e) choose this answer if none of the above is correct 11. The observation that cell structure and function are similar from organism to organism, despite differences in cell specialization and organism complexity provides evidence that ? a) all cells have evolved from a common ancestor b) cell function is independent of cell function c) all cells have the same blueprint for reproduction d) cells do not evolve e) none of these is correct Bil 255s02 – form 0 - Test 1 – page 2 12. Which of the following classes of small organic molecules found in cells can be made from a mixture of gases and water vapor presumed to be present on early Earth in a “Miller & Urey”-like experiment? a) amino acids b) sugars c) purines d) pyrimidines e) choose this answer of all of these can be made 13. The origin of life would have been enhanced by molecules that possessed the ability to catalyze reactions that lead, directly or indirectly, to the production of more molecules like themselves? a) true b) false 14. An aggregate of abiotically produced molecules, which can form microspheres that are internally chemically different from the environment, and may be metabolically active are known as? a) organelles b) protobionts c) ribozymes d) cytoplasmic vesicles e) none of the above 15. The origin of biological catalysis may be seen in novel ribozymes and deoxyzymes, molecular complexes that have ability to make copies of themselves & direct other molecules to replicate themselves. a) true b) false 16. Using DNA sequences to study the relationships among the prokaryotes, it has been proposed that all life be divided into three domains: Eukaryota, Eubacteria, and Archae. Into which of these 3 domains would you place heterotrophic bacteria as the cyanobacteria? a) Eukaryota b) Eubacteria c) Archae d) viruses e) none of these is a correct choice 17. A proteinaceous infectious molecula r particle , without RNA, whose accumulation can lead to degenerative diseases of the central nervous system is known as a? a) virus b) ribosome c) prion d) protobiont e) none of these is a correct choice 18. A molecule that can serve as both an acid and a base (water is an example of such a molecule) is a(n)? a) hydronium ion b) zwitterion c) buffer d) amphoteric molecule e) none of these 19. The ability of water to remain a liquid at room temperature (25 o C) is due to ? a) hydrogen bonding between oxygen atoms of two H 2 O molecules b) hydrogen bonding between the hydrogen atoms of two H 2O molecules c) hydrogen bonds between the hydrogen and oxygen atoms of two H 2 O molecules d) the non-polar nature of the covalent bonds in a molecule of H 2 O e) none of these is correct 20. The chemistry of life is based on the chemistry of carbon because? a) carbon has the ability to form ionic bonds with other atoms b) carbon can form up to four covalent bonds with other atoms c) carbon-carbon bonds are highly unstable d) the covalent bonds between carbon and other atoms are highly reactive e) none of these is correct 21. Which of the following molecules is (are) biological polymers ? a) starch b) DNA c) hexokinase d) cellulose e) all of these molecules are polymers 22. The functional group which makes a portion of a fatty acid molecule an acid is the? a) hydroxyl group b) carboxyl group c) phosphate group d) sulfhydryl group e) none of these 23. Triglycerides form large spherical (up to 200 nm in diameter) fat droplets in the cell cytoplasm? a) true b) false 24. The chemical properties of phospholipids which makes them important in membrane structure is because they contain both hydrophobic and hydrophilic groups. Such a property is referred to as being? a) amphipatic b) van der Waal forces c) polar d) fatty e) none of these is correct Bil 255s02 – form 0 - Test 1 – page 3 25. The monomer composed of a nitrogenous base, a 5 carbon sugar, and a phosphate is? a) an amino acid b) a nucleotide c) a nucleoside d) a pyrimidine e) none of these is correct 26. Which of the amino acid side chains below would contribute to a protein’s portion or regions being or having hydrophobic (fatty) properties? a) -CH2 -CH3 b) -CH2 -SH c) -CH2 -COOH d) -CH2 -OH e) none of these is a correct choice 27. 3-D outlines, contour, or surface shape of a molecule , as determined by the spatial orientation of atoms & functional groups, which are free to assume different positions in space without breaking any chemical bonds is known as? a) its configuration b) its conformation c) its tensegrity d) hydrophobicity e) none of these 28. An object or molecule that is not superimposible on its own mirror image is referred to as? a) a cis-trans isomer b) a chiral molecule c) an isotope d) a diastereomers e) none of these 29. A redox reaction? a) transfers a phosphate from ATP to glucose b) combines two molecules with the concomitant loss of water c) removes electrons from a donor transferring them to an acceptor d) occurs only in glycolysis e) none of these is a correct choice 30. Which of the following macromolecules are made by a condensation reaction? a) proteins b) nucleic acids c) polysaccharides d) phospholipids e) all of these macromolecules are made by a condensation reaction, which eliminates water 31. The heat content of a system (or a reaction) is measured by its? a) enthalpy b) entropy c) equilibrium constant d) amphoteric nature e) none of these 32. The pH of an amino acid where the net charge is zero is referred to as the amino acids? a) pK b) isoelectric point c) redox point d) enantiomer e) none of these 33. The chemical class that the amino acid shown to the right belongs to is most likely? a) basic amino acid b) acidic amino acid c) polar amino acid d) non-polar amino acid e) none of these is the correct class 34. The functional class of proteins that bind and carry ligands are known as? a) structural proteins b) defensive proteins c) storage proteins d) transport proteins e) none of these 35. The class of proteins that are soluble only in pure distilled water are the? a) albumins b) globulins c) glutelins d) scleroproteins e) none of these is correct 36. Two proteins that have a different primary sequence, but catalyze the same enzymatic reaction exhibit? a) site specificity b) polymorphism c) only quaternary structure d) homology e) none of these 37. The native configuration of most enzyme proteins with an interior hydrophobic area and exterior hydrophilic regions is referred to as being? a) fibrous b) helical c) globular d) a chaperone e) none of these is correct 38. Using gentle mechanical and shearing forces to disrupt cell membranes so cell contents can be released results in a liquefied “thick soup” called? a) pellet b) homogenate c) microsomes d) precipitate e) none of these 39. Mitochondria, chloroplasts, and lysosomes would most likely sediment separate from other cell components in differential centrifugation at which of the following centrifugal speeds? a) 300xG b) 10,000xG c) 100,000xG d) 250,000xG e) none of these is correct Bil 255s02 – form 0 - Test 1 – page 4 40. The separation of cellular components, independent of size, within a steep gradient of sucrose or cesium chloride is? a) velocity sedimentation b) density gradient centrifugation c) equilibrium density centrifugation d) fractionation e) none of these is correct 41. A chromatography column packed with a matrix medium that contains a molecule specific for a protein of interest is referred to as? a) paper chromatography b) ion exchange chromatography c) gel filtration chromatography d) affinity chromatography e) none of these is correct 42. A fraction of cell suspension taken off a chromatography column is suspected to contain a protein of interest in solution. To determine is it is protein we measure its absorbance in UV light. We expect that it would show max absorption at which of the following wavelengths of light? a) 280nm b) 260nm c) 500nm visible light d) green light e) none of these Fig. 1 Protein Standard Curve Fig 2 - Hexokinase umol glucose-6-P per min 0.6 Absorbance 595nm 0.5 0.4 0.3 0.2 0.1 25 20 15 10 5 0 0 0.5 0 5 10 20 30 40 50 1 1.5 2 4 8 16 32 40 60 80 umol glucose mg albumin protein 43. Using figure 1 above determine the amount of soluble protein isolated from a portion of liver cells given the following information: a 1.0 ml sample of a 50 ml liver cell homogenate reveals an absorbance at 595nm in the Bradford protein Standard Curve test of 0.45. How much protein is likely to be in the whole liver homogenate? a) 40 mg protein b) 0.45 mg protein c) 268 mg protein d) 2.0 grams protein e) none of these 44. If 7.5 mg of enzyme protein converts 225 µmoles of substrate to product in 3.0 minutes, then the correct numerical value of the specific activity of this enzyme would be? a) 225 b) 75 c) 10 d) 30 e) none of these is a correct specific activity 45. The class of enzyme, as carboxypeptidase-A, which add water across C-C bonds are known as? a) dehydrogenases b) oxidoreductases c) lyases d) transferases e) none of these is a correct choice 46. The Vmax for a native enzyme reaction is determined to be 6.6 µmoles glucose-6-P/min and the Km is shown to be 2.6 µmoles glucose. A competitive inhibitor, malonic acid, for this enzyme reaction is determined to have a Km of 4.8 µmoles of glucose. What is the ½Vmax for the malonic acid inhibited enzyme reaction? a) 6.6 µmoles glucose-6-P/min b) 13.2 µmoles glucose-6-P/min c) 3.3 µmoles glucose-6-P/min d) 2.4 µmoles glucose e) none of these answer choices is correct 47. In figure 2 above a native enzyme reaction (diamonds) and the inhibited version of the same enzyme (squares) is depicted. The Vmax of the inhibited reaction is? a) 20 µmoles glu/min b) 12.5 µmoles glu/min c) 1 µmole glucose d) 2 µmole glucose e) none of these 48. The type of enzyme inhibition exhibited by the kinetics of figure 2 is most likely? a) competitive b) non-competitive c) irreversible d) Lineweaver-Burke e) none of these Bil 255s02 – form 0 - Test 1 – page 5 49. ADP can serve as an allosteric regulator of phosphofructokinase, a key glycolytic enzyme. ADP binds directly to the active site of the enzyme phosphofructokinase. a) true b) false 50. The redox potential of a redox couple is the measure of the ability of one of its compounds to reduce another. The part of the couple which loses its electrons is called the? a) reducing agent b) oxidizing agent c) acceptor d) allosteric site e) none of these 51. Concerning glycolysis which of the following is a correct statement? a) glycolysis takes place in the cell’s cytoplasm b) ATP is generate d by substrate level phosphorylation c) ATP is consumed in order to initiate glycolysis d) a key reaction involves the reduction of NAD+ e) choose this answer if all of these are correct statements concerning glycolysis 52. The potential energy of the electrons captured into cytoplasmic NADH can be used to make ATP ’s, when these electrons are transferred to the electron transfer chain via? a) alcoholic fermentation b) lactate fermentation c) an a-glycerophosphate shuttle d) substrate level phosphorylation e) none of these is correct 53. The pyruvate dehydrogenase complex contains 3 enzyme and 5 coenzymes. One of these coenzymes is derived from the vitamin B1 . The function of this coenzyme is to destabilize the bond between the carbonyl and carboxyl groups of pyruvate. A deficiency in this coenzyme results in the disease called beriberi. This coenzyme is? a) NADH b) thiamin pyrophosphate (TPP) c) FADH2 d) coenzyme-A e) none of these 54. Substrate level phosphorylation occurs both in glycolysis and the mitochondrial Krebs’ cycle. 55. Palmitic acid is a fatty acid that contains a total of 16 carbons. If palmitic acid undergoes oxidation by fatty-acylCoA-dehydrogenase, then the number of individual acetyl-Co’A that would be produced would be? a) 16 2) 8 c) 3 d) 2 e) none of these is correct 56. A beta-barrel trans-membrane protein with a hydrophilic channel that effectively transports molecules of less than 5,000 molecular weight across the inner mitochondrial membrane is? a) ADP-ATP translocase b) ATP synthase c) porin d) malate shuttle e) none of these 57. Mitochondrial DNA codes for all of the known subunits of the mitochondrial ATP synthase? 58. Given: the measured redox potential of the following mammalian electron transfer components - cytochrome b (cyt b) is +310mV - cytochrome c (cyt c) is +650mV - coenzyme Q (CoQ) is -50.0mV - Flavin mononucleotide (FMN) is -290mV - iron sulfur protein (FeS) is -213mV a) true a) true b) false b) false The correct order for the passage of a pair of electron through these ETC components is? a) from cyt c to cyt b to CoQ to FeS to FMN b) from FMN to cyt c to cyt b to CoQ to FES b) from CoQ to FMN to FES to cyt b to cyt c d) from FMN to FeS to CoQ to cyt b to cyt c e) none of these is a correct sequence for electron transfer 59. 60. In the presence of the electron transfer chain uncoupler, dinitrophenol? a) the pH gradient across the mitochondrial membrane collapses c) the electrical charge inside the matrix becomes positive b) ATP synthesis is reduced d) all of these are correct choices ATP synthase catalyses the synthesis of ATP from ADP and phosphate, driven by a flux of protons across the membrane as the protons move down their proton gradient generated by electron transfer. The reaction catalyzed by ATP synthase is fully reversible as the enzyme can function as a hydrolyase. a) true b) false ...
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