Apps-dso.sws.iastate.edu



THIS IS NOT THE EXAM REVIEW SHEET! HELLO EVERYONE!!! These are questions from old exams that are relavent to Exam 2. I understand that there are many... however, these are an INCREDIBLY HELPFUL resource. I highly recommend running through all of them (maybe try answering 25-50 per day?) These questions are directly copied and pasted from a folder on blackboard posted by your professors. 1. A reaction will proceed spontaneously when -a. it is endergonic.*b. It is exergonic.2. A reaction will proceed spontaneously when:a. The products of the reaction have more free energy than the reactants, therefore the ΔG < 0.b. The products of the reaction have more free energy than the reactants, therefore the ΔG > 0.*c. The products of the reaction have less free energy than the reactants, therefore the ΔG < 0.d. The products of the reaction have less free energy than the reactants, therefore the ΔG > 0.e. The products of the reaction have the same amount of free energy as the reactants, therefore the ΔG = 0.3. We measure energy in the units of ______________________, and power in units of ________________. a. joules or watts, calories or kilocalories *b. joules or calories, watts or calories/day c. Gibbs free energy, entropy d. ATP, NADH 4. The manufacture of a large protein from hundreds of amino acids is likely to *a. require energy input b. release energy that can potentially be used for other purposes c. result in no change in free energy d. be exergonic, with a large negative ΔG 5.Which of the following statements is correct with respect to anabolic pathways? a. They do not depend on enzymes. *b. They consume energy to build up polymers from monomers. c. They release energy as they degrade polymers to monomers. d. They result in net production of ATP. 6. Which of the following statements correctly describe(s) catabolic pathways? a. They do not depend on enzymes. b. They consume energy to build up polymers from monomers. *c. They release energy as they break down organic molecules. d. both A and B are correct 7. Living organisms increase in complexity as they grow, resulting in an apparent decrease in their entropy. How does this relate to the second law of thermodynamics? a. Living organisms do not obey the second law of thermodynamics, which states that disorder (entropy) must increase with time. *b. Life obeys the second law of thermodynamics because living things are not closed systems – though they become more complex (ordered), they extract free energy from their surroundings to do that, and increase the entropy of their surroundings. c. Living organisms can create new free energy via photosynthesis, and use that energy to decrease their own entropy. d. Enzyme catalysts reduce the activation energy for the conversion of entropy back into free energy. 8. According to the second law of thermodynamics, which of the following statements is INCORRECT? *a. The synthesis of large molecules from small molecules is exergonic (releases free energy). b. Living organisms cannot be closed system. c. Life exists at the expense of energy derived from its environment. d. A living cell can never function indefinitely as a closed system. e. Every chemical reaction in a cell results in a loss of free energy. 9. Growing organisms increase in complexity, so their entropy must decrease. The only way to reconcile this with the second law of thermodynamics is to realize that a. Living organisms do not obey the second law of thermodynamics, which states that disorder (entropy) must increase with time. *b. Living things are not closed systems –they extract free energy from their surroundings to do biological work necessary to maintain and increase order, the entropy of the total system in which they live still increases. c. Living organisms can create new free energy via photosynthesis, and use that energy to decrease their own entropy. d. Enzyme catalysts reduce the activation energy for the conversion of entropy back into free energy. 10. The second law of thermodynamics is consistent with each of the following statements EXCEPT: a. Conversion of energy from one form to another always results in some loss of free energy. b. Without occasional input of energy, organisms would tend to fall apart. c. Cells must use energy continually to maintain their high level of organization. *d. Every energy transformation by a cell increases the order and decreases the entropy of the universe. 11. In exergonic reactions, like the oxidation of glucose, a. the end products have more total energy than the starting reactants. *b. there is a net release of free energy. c. a net input of energy from the surroundings must occur. d. the reaction cannot proceed without enzymes that lower the activation energy. 12. Which of the following is true for all exergonic reactions? a. The products have more total energy than the reactants. *b. There is a net release of free energy. c. A net input of energy from the surroundings is required for the reactions to proceed. d. The reactions are nonspontaneous. 13. The mathematical expression for the change in free energy of a system is: ?G = ?H - T?S. Which of the following is NOT CORRECT for this expression? a. ?G is the change in free energy. *b. ?H, the change in enthalpy, is defined as the energy available to do work. c. ?S is the change in entropy, a measure of randomness. d. T is the absolute temperature measured in Kelvins.14. In the following graph, the change in free energy is represented by – a. A + C or B + Cb. A or B*c. Cd. C – A or B15. In the following graph, both the red and blue curves represent the same chemical reaction. In one case an enzyme is present and in the other case an enzyme is not present. Which curve likely represents a reaction with enzyme present?a. the red curve.*b. the blue curve.c. the red curve minus the blue curve.16. Which of the following best describes the reaction illustrated here? *a. negative ?G, potentially spontaneous b. positive ?G, nonspontaneous c. positive ?G, exergonic d. negative ?G, endergonic 17. A chemical reaction occurs spontaneously with the release of energy. Which of the following must be true for that reaction? a. ?G > 0 b. ?G = 0 *c. ?G < 0 d. T?S < 0 18. ATP is produced by _______ , ________ reactions and is used to drive ________, ________ reactions. What words filled in these four spaces (in order) result in a true statement? a. endergonic, catabolic exergonic, anabolic b. exergonic, anabolic endergonic, catabolic, *c. exergonic, catabolic endergonic, anabolic d. endergonic, anabolic exergonic, catabolic19. ATP generally energizes cellular processes by which of the following? a. releasing heat upon hydrolysis b. acting as a catalyst *c. direct chemical transfer of a phosphate group d. releasing ribose electrons to drive reactions 20. Why is ATP an important molecule in metabolism? a. Its hydrolysis provides an input of free energy for exergonic reactions. *b. It provides energy coupling between exergonic and endergonic reactions. c. Its terminal phosphate group is highly unstable, and thus reactive. d. A and B are both correct 21. Which of the following is most similar in structure to ATP? a. a steroid, like cholesterol b. a DNA double helix *c. a nucleotide d. an amino acid with three phosphate groups attached e. a phospholipid 22. Which of the following statements regarding ATP is (are) correct? a. ATP serves as a main energy shuttle inside cells. b. ATP drives endergonic reactions in the cell by transfer of the phosphate group to specific reactants. c. The regeneration of ATP from ADP and phosphate is an endergonic reaction, requiring energy input. *d. All of the above are correct. 23. How could you tell whether or not a particular reaction you were studying was enzyme-catalyzed? a. Remove proteins from the reaction mixture and see what happened to the reaction rate. b. Try different concentrations of the reactants to see if the reaction rate first increased with reactant concentration, then stopped changing even though reactant concentration was further increased. c. Measure the activation energy. *d. A and B would both provide useful information, but C would not. 24. Enzymes speed the rate of substrate conversion to product by which of the following mechanisms? a. increasing the energy of the substrate b. decreasing the energy of the product c. decreasing the ?G of the reaction *d. decreasing the activation energy of the reaction 25. The reaction A + B => C + D illustrated here shows the change in reaction energetics that resulted when a catalytic enzyme was added, and the reaction rate went way up. Which of the following distances labeled on the graph represents the activation energy required for the enzyme-catalyzed reaction? a. a *b. b c. c d. d e. e 26. Which of the following statements about enzymes is FALSE? a. Enzyme catalysis is dependent on the three-dimensional structure or conformation of the enzyme. *b. Enzymes provide activation energy for the reaction they catalyze. c. Enzymes are composed primarily of protein, but they may bind nonprotein cofactors. d. Enzyme activity can be inhibited by other molecules, even if they do not bind to the active site. 27. The effect on the reaction illustrated here of adding a catalytic enzyme would be to a. reduce the free energy of the reactants. b. increase the free energy of the products. c. reverse the direction of the reaction. *d. reduce the value labeled EA, and increase the rate of the reaction. 28. A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because a. the starch solution has less free energy than the sugar solution. b. the hydrolysis of starch to sugar is endergonic. *c. the activation energy barrier is too high for the reaction to go very fast at room temperature. d. starch cannot be hydrolyzed in the presence of water. 29. What is the term that best describes the metabolic pathway in which glucose (C6H12O6) is degraded to carbon dioxide (CO2) and water? *a. cellular respiration b. glycolysis c. fermentation d. citric acid cycle e. oxidative phosphorylation 30. Most of the ATP made during cellular respiration is produced by a. glycolysis. *b. oxidative phosphorylation. c. substrate level phosphorylations. d. direct synthesis of ATP by the tricarboxylic acid cycle. 31. Which statement about the subcellular localization of the respiratory pathways is FALSE? If they are all true choose E. a. Glycolysis reactions are located in the cytosol (the cytoplasm of the cell). b. The citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle) occurs within the mitochondrial matrix c. The electron transport chain and ATP synthase are located in the inner mitochondrial membrane d. Pyruvate must be transported from the cytosol to the mitochondrial matrix in oxidative respiration. *e. All of the above are correct 32. In the following graph, the same chemical reaction is represented. The different curves either have no inhibitor present, a non-competitive inhibitor, or a competitive inhibitor. Which curve represents when a non-competitive inhibitor is present? a. Ab. B*c. C33. In the following graph, the same chemical reaction is represented. The different curves either have no inhibitor present, a non-competitive inhibitor, or a competitive inhibitor. Which curve represents when a competitive inhibitor is present? a. A*b. Bc. C34. A drug is designed to make the glycolytic pathway more productive. What part of the cell would the drug need to be delivered to for it to directly affect this pathway?a. mitochondrial matrix*b. cytosol/cytoplasmc. mitochondrial intermembrane spaced. nucleuse. chloroplast35. What molecule is produced by glycolysis, and is then imported into the mitochondria to enter into the TCA cycle?a. glucoseb. NADPH*c. pyruvated. citric acid36. The ATPs generated during glycolysis are formed by which mechanism, substrate-level phosphorylation or oxidative phosphorylation?*a. Substrate-levelb. Oxidative phosphorylation37. A proton ionophore is a substance that creates a proton leak in a membrane. What might you predict that a proton ionophore would do in mitochondria?a. Nothing.b. Create a greater proton motive force.c. Block electrons from being transported from one carrier to another.*d. Prevent the synthesis of ATP.e. None of the above.38. A drug that increases the number of NADH & FADH2 molecules produced through the citric acid cycle/Krebs cycle and has no other effects on the cell would theoreticallya. decrease the activity of ATP synthase.b. decrease the cell’s ability to manufacture glycerol.*c. increase the number of ATPs produced per glucose.d. increase lactic acid production.e. decrease the cell’s need for oxygen.39. A substance that increases the number of protons (H+) in the mitochondrial matrix (and has no other effect on the cell) would theoretically ____.a. increase the ATP yield of glycolysisb. decrease ATP yield in the citric acid cycle/Krebs cyclec. inhibit pyruvate metabolism*d. decrease the ATP yield in oxidative phosphorylatione. increase the ATP yield of fermentation40. Which of the following statements concerning the metabolic degradation of glucose (C6H12O6) to carbon dioxide (CO2) and water is (are) true? a. The breakdown of glucose to carbon dioxide and water is exergonic, releasing free energy. b. The breakdown of glucose to carbon dioxide and water in a cell is usually coupled to the production of more than 25 ATP. c. The breakdown of glucose to carbon dioxide and water is completed in the reactions of the citric acid cycle in the mitochondrial matrix. *d. All of the above are true. 41. Which of the following produces the most ATP when a glucose molecule (C6H12O6) is oxidized to carbon dioxide (CO2) and water? a. glycolysis b. fermentation c. oxidation of pyruvate to acetyl CoA d. the citric acid cycle *e. oxidative phosphorylation (electron transport and chemiosmosis) 42. The citric acid cycle is a “cycle” because:a. CO2 is released at various steps in the cycle and then fixed again.*b. oxaloacetate is regenerated in each round of the cycle.c. ATP is hydrolyzed, then resynthesized.d. All of the above.e. None of the above43. [180] is an isotope of Oxygen. In the experiment below, [180] is present either in water (Experiment 1), or in carbon dioxide (Experiment 2). Which of the flasks in the experiment below will produce 18O2in the presence of light?*a. Experiment 1b. Experiment 2c. Both Experiment 1 and 2d. Neither Experiment 1 or 244. [180] is an isotope of Oxygen. It contains extra a. Protons *b. Neutrons c. Electrons45. A change in an enzyme's three-dimensional shape and disruption of normal function, due to alteration of hydrogen bonds or ionic bonds caused by an increase in temperature, is best labeled: a. hydrolysis b. destabilization c. allosteric inhibition *d. denaturation 46. Shutdown of an early step in a metabolic pathway by an end product of that pathway is best described, without any additional information, as *a. feedback inhibition. b. allosteric inhibition. c. noncooperative inhibition. d. competitive inhibition. 47. The most important function of long-chain polypeptides in organisms is in a. storage of chemical potential energy for later use. *b. catalysis that speeds up the rate of important biochemical reactions. c. coding of genetic information in a form that can be duplicated and partitioned when cells divide. d. All of the above are important functions of long-chain polypeptides. 48. Which of the following is FALSE? a. Enzyme catalysis is dependent on the pH and temperature of the reaction environment. b. Enzyme catalysis is dependent on the three-dimensional structure or conformation of the enzyme. *c. Enzymes provide activation energy for the reaction they catalyze. d. Enzyme activity can be inhibited by a molecule that binds to the enzyme far from the active site.49. Which of the following are CORRECT statements about enzymes? a. Enzymes may require a nonprotein cofactor or metal atom for catalysis to take place. b. An enzyme's catalytic rate is likely to change if its three-dimensional structure is altered. c. Enzyme activity is influenced by physical and chemical environmental factors such as pH and temperature. d. Enzymes increase the rate of chemical reaction by lowering activation energy barriers. *e. All of the above are correct. 50. Phosphofructokinase is a protein that catalyzes a reaction that controls the rate of glycolysis in animal cells. The term kinase means that this protein a. breaks a large molecule down to smaller parts (catabolism) b. catalyzes a reaction that produces ATP c. can be allosterically activated by molecules that bind to regions away from its active site. *d. adds a phosphate group to or removes a phosphate group from another molecule. 51. Which type of inhibitor binds to the active site of an enzyme? a. allosteric inhibitor *b. competitive inhibitor c. non-competitive inhibitor d. feedback inhibitor 52. Hemoglobin is a tetramer, composed of four polypeptide subunits. When one of the subunits binds an oxygen molecule, the affinity for oxygen of other subunits increases, so additional oxygen uptake becomes more likely. This is best described as the result of: a. enzyme saturation b. allosteric inhibition *c. allosteric activation d. oxidative damage 53. Which of the following statements about NAD+ is FALSE? a. NAD+ is reduced to NADH during both glycolysis and the citric acid cycle. *b. NAD+ has more chemical potential energy than NADH. c. NAD+ can receive electrons for use in electron transport and oxidative phosphorylation. d. In the absence of NAD+, glycolysis cannot proceed. 54. The ATP made during glycolysis is generated by *a. transfer of phosphate from a phosphorylated carbon molecule to ADP, called substrate-level phosphorylation. b. electron transport. c. chemiosmosis. d. oxidation of NADH to NAD+. 55. In addition to ATP, other end products of glycolysis include: a. CO2 and H2O b. CO2 and pyruvate *c. NADH and pyruvate d. CO2 and NADH 56. Where does glycolysis takes place? a. mitochondrial outer membrane b. mitochondrial inner membrane c. mitochondrial intermembrane space *d. cytosol (the cytoplasm of the cell) 57. You are studying the biochemistry of muscle cell samples from world-class sprinters, and isolate a compound that is highly soluble in water, and varies in molecular weight, but averages about C60H100O50. Cells without this substance run out of ATP very quickly when oxygen is absent, but work for longer periods if this substance is present. The substance is most likely to be a a. Lipid b. Protein *c. Carbohydrate d. Nucleic acid e. Enzyme 58. During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is a. transferred to ADP, forming ATP. b. transferred directly to ATP. *c. retained in the pyruvate. d. stored in the NADH produced. 59. Which statement is NOT TRUE about glycolysis? If all are true, select alternative D. a. Two ATP are needed per glucose in the energy investment phase of glycolysis b. Four ATP per glucose are produced during the energy yielding phase of glycolysis c. The two NADH produced per glucose can be oxidized back to NAD+ by the mitochondrial electron transport chain. *d. All of the above are true. 60. If all of the molecules of an enzyme are saturated with substrate, the most effective way to obtain a faster yield of products (increase the reaction rate) is to *a. add more of the enzyme. b. heat the solution to 90°C. c. add more substrate. d. add an allosteric inhibitor. 61. If an enzyme is added to a solution where the substrates and products are in equilibrium, what would occur? a. Additional product would be formed. b. Additional substrate would be formed. c. The reaction would change from endergonic to exergonic. d. The free energy of the system would change. *e. Nothing; the reaction would stay at equilibrium. 62. Where does the Calvin cycle take place?*a. stroma of the chloroplastb. thylakoid membranec. cytoplasm surrounding the chloroplastd. chlorophyll moleculee. outer membrane of the chloroplast63. In a plant cell, where are the ATP synthetase complexes located?a. A. stroma of the chloroplastb. B. thylakoid membranec. C. outer membrane of the chloroplastd. D. inner membrane of the mitochondria*e. choices B and D are both correct64. What key component is necessary for photosystems to harvest light?a. vesiclesb. NADP reductase*c. pigment moleculesd. ATP synthasee. Calvin cycle65. Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?a. CO2 and glucoseb. H2O and O2c. ADP, Pi, and NADP+d. electrons and H+*e. ATP and NADPH66. Which of the following are true about photorespiration?a. A. It is an apparently wasteful side reaction of ribulose bisphosphate carboxylase (Rubisco).b. B. It is a useful supplement to cellular respiration.c. C. It is minimized in C4 plants due to specialized photosynthetic pathways and leaf architecture.d. All of the above.*e. Choices A and C are both correct.67.Which of the following is NOT a result of the citric acid cycle? a. Oxidation of pyruvate to CO2 b. Reduction of NAD+ to NADH c. Production of ATP through substrate level phosphorylation *d. Partial oxidation of glucose in the absence of oxygen to produce ATP at low rates during anaerobic conditions. 68. Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate? a. glucose-6-phosphate b. glyceraldehyde-3-phosphate c. oxaloacetate *d. acetyl CoA ?69. Which is the oxidized form??*a. NAD+ b. NADH 70. Photosystem II strips electrons from chlorophyll and delivers them to the chloroplast electron transport (cytochrome) chain.? Where do the replacement electrons come from?a. splitting O2???? b. photosystem I *c. splitting H2O d. splitting CO2 e. NADPH 71. Where is the chlorophyll located in a plant? a. Cristae b. Plasma membrane of the cell c. Outer membrane of the chloroplast *d. Thylakoid membrane e. Stroma 72. How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate, and eventually emerge as CO2? *a. 2 b. 4 c. 6 d. 8 73. 1.5 g of radish seeds in each of three dishes. The following conditions arecreated for each dish and incubated at room temperature: The dry biomass of three treatments at the end of the experiment is shown above.Most of the biomass that accumulates in the presence of light and water comes from: a. water during photosynthesis. b. the building of carbohydrates during respiration. c. the release of CO2 during respiration. *d. the incorporation of CO2 into carbohydrates during the Calvin cycle. 74. All of the following are products of the citric acid cycle EXCEPT a. ATP. b. NADH. c. FADH2. d. carbon dioxide. *e. water 75. Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? a. glycolysis and the oxidation of pyruvate to acetyl CoA *b. oxidation of pyruvate to acetyl CoA and the citric acid cycle c. the citric acid cycle and oxidative phosphorylation d. oxidative phosphorylation and fermentation e. fermentation and glycolysis 76. Which statement about the formation of water by the mitochondrial electron transport chain is TRUE? *a. The electrons come from carbohydrates and the oxygen come from O2. b. The ?G is positive. c. Energy from ATP is required to make the reactions occur. d. Cytochromes do not play any role in the process. 77. Which of the following statements about the chemiosmotic mechanism of ATP synthesis is TRUE? a. electron transport from NADH to O2 pumps H+ from the intermembrane space into the mitochondrial matrix. b. The high concentration of H+ in the mitochondrial matrix pulls water into the matrix through the ATP synthase channel by osmosis, and the energy in this water flow is used to power ATP synthesis. *c. H+ movement down a concentration gradient from the intermembrane space into the mitochondrial matrix through ATP synthase results in ATP synthesis d. All these statements describe parts of the chemiosmotic mechanism. 78. A major function of the mitochondrial inner membrane is the conversion of energy from electrons to the stored energy of the phosphate bond in ATP. To accomplish this function, the inner mitochondrial membrane must have all of the following features EXCEPT a. carrier proteins to accept electrons from NADH. b. ATP synthase as an integral protein spanning the width of the membrane. c. the electron transport chain of proteins. *d. high permeability to protons (H+ ions). 79. Which steps in the metabolic pathway of cellular respiration occur in the cytosol? *a. glycolysis b. pyruvate break down c. citric acid cycle d. oxidative phosphorilation e. all but d f. a & b g. none of the above 80. The oxygen consumed during cellular respiration is involved directly in which process or event? a. glycolysis *b. accepting electrons (and H+) at the end of the electron transport chain, forming water c. the citric acid cycle d. the oxidation of pyruvate to acetyl CoA e. the phosphorylation of ADP to form ATP 81. Where are the proteins of the respiratory electron transport chain located? a. cytosol b. mitochondrial outer membrane *c. mitochondrial inner membrane d. mitochondrial intermembrane space e. mitochondrial matrix 82. The primary role of molecular oxygen (O2) in cellular respiration is to a. yield energy in the form of ATP as it is passed down the respiratory chain. *b. act as an acceptor for electrons and hydrogen, forming water. c. combine with carbon, forming CO2. d. react with pyruvate to form lactate or ethanol, regenerating NAD+. 83. During aerobic cellular respiration, a proton gradient in mitochondria is generated by ________ and used primarily for ________. *a. the electron transport chain; ATP synthesis b. the electron transport chain; substrate-level phosphorylation c. glycolysis; production of H2O d. fermentation; NAD+ reduction 84. Anaerobic fermentation adds reactions to glycolysis in which ________ is ________. a. NAD+; oxidized to NADH *b. NADH; oxidized to NAD+ c. pyruvate; converted to acetylCoA d. ethanol; oxidized 85. Each of the following can be converted to an intermediate of glycolysis and produce some ATP without entering the citric acid cycle EXCEPT *a. fatty acids b. some amino acids c. glucose and sucrose d. glycerol e. starch and glycogen 86. When oxygen is in short supply, your muscle cells convert pyruvate produced by glycolysis to ________, and in this step gain ________. *a. lactate; NAD+ which permits glycolysis to continue. b. alcohol; CO2 c. alcohol; ATP d. ATP; NADH287. Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? a. pyruvate b. malate or fumarate *c. acetyl CoA d. alpha-ketoglutarate e. succinyl CoA 88. In fermentation by yeast, NAD+ is regenerated from NADH during the *a. conversion of pyruvate to ethanol (ethyl alcohol). b. conversion of pyruvate to acetyl CoA. c. conversion of pyruvate to lactate. d. phosphorylation of ADP to form ATP. 89. Which of the following normally occurs in your cells regardless of whether or not oxygen (O2) is present? *a. glycolysis b. fermentation c. conversion of pyruvate to lactate d. citric acid cycle e. oxidative phosphorylation (chemiosmosis) 90. The following graph shows how the reaction rate for an enzyme catalyzed reaction varied over a range of substrate (reactant) concentrations. The thin (gray or magenta) line (upper curve) shows reaction rates in a control experiment, and the thick black line (lower curve) shows reaction rates after the addition of a small molecule (called X) that is neither a reactant nor a product in the reaction. These data suggest that molecule X …? ? a. binds to the active site of the enzyme, blocking access of the substrate. b. is a competitive inhibitor of the reaction. *c. is a non-competitive (allosteric) inhibitor, that does not block the active site but changes the conformation of the enzyme to reduce its activity. d. activates the enzyme, because the reaction rate reaches a maximum at lower substrate concentrations. 91. As ATP levels in the cytoplasm of a cell increase, the rate of glycolysis is likely to________.a. go up, because more ATP is available for the energy investment phase of glycolysis. *b. go down, because elevated ATP results in feedback inhibition of phosphoglucokinase. c. remain unchanged, because the rate of glycolysis is controlled by the availability of oxygen. d. slow, because NAD+ is used up. 92. An enzyme whose regulation by a variety of other molecules is important in controlling the rate of glycolysis in a cell is a. coenzyme A b. pyruvate carboxylase *c. phosphofructokinase d. isomerase 93. Citric acid cycle intermediates, like oxaloacetate, alpha ketogluterate, succinate, fumerate, and malate a. carry electrons in the electron transport chain that ends in the conversion of O2 to H2O. b. are specialized molecules that are useful only in the citric acid cycle, because removing them would break the cycle. *c. are important as building materials for other organic molecules, in addition to their role in the citric acid cycle. d. are converted to pyruvate at the end of the citric acid cycle reaction sequence. 94. Trans-fats are are a. rich in cholesterol *b. unsaturated, and contain one or more double bonds. c. saturated, and more abundant in plant oils than in fish oils. d. phospholipids, with both polar and non-polar regions. 95. The following graph shows how the reaction rate for an enzyme catalyzed reaction varied over a range of substrate (reactant) concentrations. The thin gray (or magenta) line (upper curve) shows reaction rates in a control experiment, and the darker (or blue) line (lower curve) shows reaction rates after the addition of a small molecule (called X) that is neither a reactant nor a product in the reaction. These data suggest that molecule X … ? a. binds to the active site of the enzyme, blocking access of the substrate. *b. is a competitive inhibitor of the reaction. c. is a non-competitive (allosteric) inhibitor, that does not block the active site but changes the conformation of the enzyme to reduce its activity. d. activates the enzyme, because the reaction rate reaches a maximum at lower substrate concentrations. DNA/genetics96. When Hershey/Chase performed phage infection experiments, what compounds did they use to label and detect DNA and protein?a. 35S was used to label DNA, and 32P was used to label protein.*b. 35S was used to label protein, and 32P was used to label DNA.97. Choose the list of three terms that correctly fill the blanks in the following sentence:The molecules illustrated here are ________________________ that combine with _________________________ and with a ___________________ group to form monomers that can combine to make DNA. a. pyrimidines, ribose, amino b. purines, ribose, phosphate *c. purines, deoxyribose, phosphate d. pyrimidines, deoxyribose, ATP 98. Hydrogen bonding between nitrogenous bases is essential for correct replication of DNA. Which of the following base pairs forms two hydrogen bonds in DNA? a. Adenine - Guanine b. Adenine - Cytosine *c. Adenine – Thymine d. Adenine - Adenine 99. The structural feature that allows near-perfect copying of DNA molecules is a. their sugar-phosphate backbone. *b. the capability of its nitrogenous bases to form specific hydrogen bonds that lead to matching of specific pairs of nucleotides. c. disulfide bonds that hold the two helixes together. d. the three-component (base, sugar, and phosphate) structure of the nucleotides, because all three must be matched to make a perfect copy. 100. In your body, the most important function of ribonucleic acid (RNA) is to a. transmit genetic information to offspring. *b. direct the synthesis of protein. c. serve as a template for the synthesis of a complementary copy, thus ensuring genetic continuity. d. act as a template directing the synthesis of DNA. 101. The two strands making up the DNA double helix molecule a. cannot be separated. b. contain ribose and deoxyribose in opposite strands. *c. are held together by hydrogen bonds. d. are attached via ester bonds between phosphates that hold the strands together. 102. In the double helix structure of nucleic acids, cytosine hydrogen-bonds to a. deoxyribose. b. adenine. c. thymine. *d. guanine. 103. The pyrimidine bases in DNA are—a. Cytosine, thymine and uracilb. Adenine and guanine*c. Cytosine and thymined. Thymine, guanine and cytosinee. Adenine, uracil and guanine104. The purine bases in DNA are— a. Cytosine, thymine and uracil *b. Adenine and guanine c. Cytosine and thymine d. Thymine, guanine and cytosine e. Adenine, uracil and guanine 105. How many bands of DNA would you expect to see in the cesium gradient above after 3 generations if the mechanism of DNA replication was semi-conservative?a. 1 band that is half heavy*b. 2 bands, one is light and the other half heavyc. 3 bands, one is heavy, one is half-heavy, and one is lightd. 2 bands, one is heavy and one is light106. Which of the four structures labeled A, B, C and D in the figure is best described as a nucleotide? a. A *b. B c. C d. D 107. Which of the following is the best description of the class of molecules known as nucleotides? a. a nitrogenous base linked to a phosphate group b. a nitrogenous base linked to a pentose (5 carbon) sugar *c. a molecule including a nitrogenous base, a pentose (5 carbon) sugar and a phosphate group d. a phosphate group linked to an adenine or uracil e. a pentose sugar linked to a purine or pyrimidine 108. What is the function of helicase during DNA replication?*a. It separates the two strands of the double helix.b. It relieves the overwinding of DNA ahead of the replication fork due to DNA strand separation.c. It synthesizes the RNA primers used to initiate DNA replication.d. It joins the Okazaki fragments together.109. What is the function of topoisomerase during DNA replication?a. It separates the two strands of the double helix.*b. It relieves the overwinding of DNA ahead of the replication fork due to DNA strand separation.c. It synthesizes the RNA primers used to initiate DNA replication.d. It joins the Okazaki fragments together.110. What is the function of primase during DNA replication?a. It separates the two strands of the double helix.b. It relieves the overwinding of DNA ahead of the replication fork due to DNA strand separation.*c. It synthesizes the RNA primers used to initiate DNA replication.d. It joins the Okazaki fragments together.111. What is the function of ligase during DNA replication?a. It separates the two strands of the double helix.b. It relieves the overwinding of DNA ahead of the replication fork due to DNA strand separation.c. It synthesizes the RNA primers used to initiate DNA replication.*d. It joins the Okazaki fragments together.112. Which of the following statements about DNA replication is NOT correct?a. Leading strand synthesis is continuous, while lagging strand synthesis is discontinuous.b. Both leading and lagging strands are synthesized in the 5’ to 3’ direction.*c. Leading strand synthesis is conservative, while lagging strand synthesis is semi-conservative.d. Completion of the lagging strand requires ligation of Okazaki fragments.113. How are telomeres made?a. By ligation of adjacent Okazaki fragments.*b. Telomerase synthesizes them by copying the telomerase RNA.c. By telomerase which is capable of synthesizing DNA in the 3’ to 5’ direction.d. By fusion of adjacent replicons.114. Eukaryotic chromosomes have telomeres that protect the terminal nucleotides from degradation by nucleases. Bacterial chromosomes do not need telomeres becausea. bacterial DNA replication has no lagging strand synthesis, so there is no overhang to protect.*b. bacterial chromosomes are circular.c. bacteria have specialized proteins that protect the ends of their chromosomes.d. bacterial DNA polymerases can synthesize DNA bidirectionally.e. bacterial chromosomes have a single origin of replication at one end of each linear chromosome.115. What are the repeating DNA sequences at the ends of chromosomes that protect them from loss of important DNA during replication? *a. Telomeresb. Telomerasec. Repliconsd. Primerse. Promoters116. Which of the following statements about nucleosomes are correct?a. Contain about 150 bp of DNA wrapped around histonesb. The histones are called H1, H2A, H3 and H4c. The histones are basic proteins which is important to bind DNAd. Nucleosomes represent the first level of compaction of the eukaryotic chromosome*e. All of the above117. During translation, what is the direction of polypeptide synthesis?a. From 5’ to 3’b. From 3’ to 5’*c. From N-terminal to C-terminald. From C-terminal to N-terminale. From positive to negative118. During DNA replication, what is the direction of DNA synthesis?*a. From 5’ to 3’b. From 3’ to 5’c. From N-terminal to C-terminald. From C-terminal to N-terminale. From positive to negative119. The following statements are consistent with the central dogma –a. A. During transcription, DNA is copied into RNA.b. B. During translation, RNA sequences code for polypeptide sequences.c. C. The process of transcription produces a polypeptide sequence.d. D. DNA is translated into ribonucleotides.*e. A and B.f. C and D.120. Which of the following best summarizes the central dogma?a. DNA is translated into RNA, and RNA is transcribed into polypeptides.b. RNA is translated into DNA, and DNA is transcribed into polypeptides.*c. DNA is transcribed into RNA, and RNA is translated into polypeptides.d. polypeptides translate DNA into ribosomese. All of the above.121. Using the single-letter amino acid codon table shown below, translate the following mRNA:5’-AUG,GCG,AGA,GUU,GAG,CUG,UGA-3’ a. MAGICAL*b. MARVELc. MONSTERd. MAYHEM122. The diagram shows a step in the experiment by Avery, MacCleod and McCarty in which they demonstrated that DNA was the genetic material. Recall that they made an extract from the S strain bacteria and mixed the extract with the R strain. Why did the experimenters treat sample C with DNase?a. To activate the DNA.b. To allow the DNA to enter the R strain bacteria.*c. To demonstrate that DNA in the extract was the genetic material.d. To purify the DNA from other materials in the extract.e. All of the above. 123. Why did the experimenters treat sample D with RNase?a. To activate the DNA.b. To demonstrate that DNA makes RNA.*c. To demonstrate that RNA is not the genetic material.d. To purify the DNA from other materials in the extract.e. All of the above.124. Why did the experimenters treat sample E with Protease? a. To activate the DNAb. To allow the DNA to enter the R strain bacteria.c. To purify the DNA from other materials in the extract.*d. To demonstrate that protein is not the genetic material.e. All of the above125. In the structure of DNA …. (finish the sentence) a. the “backbone” of each strand consists of deoxyribose sugars and phosphates linked together by phosphodiester bonds. b. the two strands of the helix are bonded together by hydrogen bonds between purine and pyrimidine bases. c. the two strands run antiparallel to each other meaning that one strand runs 5’ to 3’ and the other from 3’ to 5’. *d. All of the above.? 126. In the structure of DNA …. (finish the sentence) *a. the “backbone” of each strand consists of deoxyribose sugars and phosphates linked together by phosphodiester bonds. b. the two strands of the helix are bonded together by hydrogen bonds from one purine to another purine and from one pyrimidine to another pyrimidine. c. the two strands run parallel to each other meaning the purines base pair with pyrimidines and pyrimidines base pair with purines. d. All of the above. 127. A DNA strand in double-stranded DNA is based paired with its complementary strand. The strand complementary to a strand with the sequence 5’-GCAAGTCATGCCGAAT-3’ would read as follows: a. 5’-CGTTCAGTACGGCTTA-3’ *b. 5’-ATTCGGCATGACTTGC-3’ c. 5’- GCAAGTCATGCCGAAT-3’ d. 5’-ATGCAGTTACAATGCA-3’ 128. A DNA strand in double-stranded DNA is based paired with its complementary strand. The strand complementary to a strand with the sequence 5’-ATGCAGTTACAATGCA-3’ would read as follows: a. 5’-ATTGCCGTACTGAACG-3’ b. 5’-TAACGGCATGACTTGC-3’ c. 5’-ATGCAGTTACAATGCA-3’ *d. 5’-TGCATTGTAACTGCAT-3’ 129. DNA synthesis is said to semi-conservative because …….. (finish the sentence). a. the parental DNA strands are not always conserved, only sometimes, during DNA replication. *b. only one parental strand is found in each sister chromatid following DNA replication. c. two parental strands are found in one sister chromatid and two daughter strands are found in the other sister chromatid following DNA replication. d. the daughter strands have to be separated during DNA replication. e. none of the above. 130. In this very simple diagram of a DNA replication fork shown above, which red strand(s) is the lagging DNA strand?*a. Ab. Bc. A and Bd. Neither A nor B131.In this very simple diagram of a DNA replication fork shown above, which red strand(s) is the leading DNA strand?a. A*b. Bc. A and Bd. Neither A nor B132. During DNA synthesis on the lagging strand …… (finish the sentence) a. DNA is made in pieces called Okazaki fragments. b. DNA synthesis is initiated by RNA primers. c. DNA primase hops back to the opening of the replication fork to make additional RNA primers. *d. All of the above. e. None of the above. 133. During DNA replication, the function of DNA polymerase is: a. to removes tightened coils ahead of DNA replication folk. b. to separate double stranded DNA into single strands. *c. to synthesize DNA in both leading and lagging strands. d. to synthesize short RNA primers. e. to covalently attaches adjacent Okazaki fragments in the lagging strand. 134. Nucleosomes: a. are DNA structures with histone proteins wrapped around them. *b. are composed of DNA wrapping around core histones and linked together by a DNA linker region to which histone H1 is bound. c. are about 30 nanometers in diameter. d. All of the above e. None of the above 135. The first order of chromatin fold is: a. the formation of 30 nanometer chromatin fiber. b. the formation of radial loops from the 30 nanometer chromatin fiber *c. the formation of nucleosome d. all of the above e. none of the above 136. The second order of chromatin fold is: *a. the formation of 30 nanometer chromatin fiber. b. the formation of radial loops from the 30 nanometer chromatin fiber. c. the formation of nucleosome d. all of the above e. none of the above ?137. The cartoon below depicts DNA replication. ? The mechanism of replication is thought to be a. Conservative b. Dispersive *c. Semi-conservative 138. Different fluorescent dyes were be used to label individual chromosomes in the image below.? How would you interpret this image of an interphase nucleus??Cremer and Cremer, 2001 a. Chromosomes occupy overlapping domains in the nucleus *b. Chromosomes have mostly individual domains in the nucleus c. Chromosomes are a mix of DNA and proteins d. Chromosomes do not contain protein during interphase 139. A repeating DNA sequence at the end of chromosomes that prevents them from losing base pair sequences at their ends and from fusing together is— *a. A telomere b. A telomerase c. A replicon d. A primer e. A promoter 140. In eukaryotic cells histones bind to DNA to form chromatin.? What is the basic (and smallest) organizational unit of chromatin? a. Double helix b. 30 nanometer fiber *c. nucleosome d. ribosome e. circular DNA Gene expression141. Which of the following is the correct RNA transcript of the DNA template strand?a. T G A C G G G T A C T C G C T G G G G A A G C C C G A G C C C C T T A C T T A G C b. A C T G C C C A T G A G C G A C C C C T T C G G G C T C G G G G A A T G A A T C G *c. A C U G C C C A U G A G C G A C C C C U U C G G G C U C G G G G A A U G A A U C G d. U G A C G G G UA C U C G C U G G G G A A G C C C G A G C C C C U U A C U U A G C 142. The following is/are true about Aminoacyl-tRNA Synthetases – a. They catalyze the attachment of amino acids to tRNAs. b. They are enzymes and comprise a family of proteins. c. They utilize energy from ATP to attach amino acids to tRNAs. d. Referred to as the second genetic code because they are able to recognize the appropriate tRNA and the corresponding amino acid. *e. All of the above. 143. Which strand gets transcribed into mRNA?a. The coding strand. It is read 3’ to 5’ by RNA polymerase. *b. The template strand. It is read 3’ to 5’ by RNA polymerase. c. The coding strand. It is read 5’ to 3’ by RNA polymerase. d. The template strand. It is read 5’ to 3’ by RNA polymerase. 144. The resulting mRNA from transcription has the following polarity – a. 3’to 5’ *b. 5’to 3’ c. 5’to 5’ d. 3’to 3’ 145. What parts of the following structural gene are represented in processed mRNA?? *a. The exons only b. The introns only c. The exons and introns d. The promoter and exons e. The promoter and introns 146. The following statement is true about introns and exons –? a. Only exons are transcribed, introns are spliced from the RNA b. Only introns are transcribed because exons are spliced from the DNA *c. Both introns and exons are transcribed, introns are spliced from the mRNA. d. The promoter, exons, and introns are transcribed. Exons are spliced from the mRNA. 147. What is the promoter region?a. It is a region of RNA that binds to the RNA polymerase and initiates transcription. b. It is a component of each type of RNA. c. It is responsible for the selective nature of transcription. *d. It is a region of a parent DNA strand that binds to the RNA polymerase and initiates transcription.? 148. Anticodon is the term applied to— *a. the part of the tRNA that interacts with the codon b. the list of amino acids that corresponds to the genetic code c. the concept that multiple codons sometimes code for a single amino acid d. the several three-nucleotide stretches that code for "stop" e. the part of the tRNA that binds to an amino acid 149. Which of the following may be involved in combinatorial control of eukaryotic gene expression – a. Activator proteins b. Repressor proteins c. DNA methylation d. Alteration of chromatin structure *e. All of the above 150. Histone acetyltransferase and ATP-dependent chromatin remodeling enzymes convert the chromatin from the closed conformation to the open conformation. What effect does this have on transcription? a. Splicing is increased b. Transcription is shut down c. RNA elongation is repressed d. Small effector proteins are excluded from the genes *e. RNA polymerase is able to bind and initiate transcription of the gene 151. In eukaryotic genes, exons are in the _________ regions of a gene and are ________. a. coding, spliced out b. noncoding, spliced out *c. coding, not spliced out d. nocoding, not spliced out 152. In eukaryotic genes, introns are in the _________ regions of a gene and are ________. a. coding, spliced out *b. noncoding, spliced out c. coding, not spliced out celd. nocoding, not spliced out?153. Mature mRNAs have 100-200 adenine nucleotides added to 3’-end. Which is true for the poly A tails: *a. It increases stability and life span of mRNA. b. It is encoded by gene sequence. c. It ensures proper exit of mRNA. d. It binds to ribosome.154. The diagram above shows the three-dimensional structure of a tRNA.What can be said about tRNAs?a. An amino acid is linked to the 3’-end by an aminoacyl-tRNA synthetase.b. There is a different aminoacyl-tRNA synthetase for every amino acid.c. The GGC sequence is the anticodon recognizes and base pairs with codons in the mRNA.*d. All of the above.e. None of the above155. Table 12.1 is a table of codons from your textbook.Using the table above, translate the following mRNA sequence from the start codon to the stop codon (you need to find the translation start codon first): 5’-UGCCAUGGCACCUGACUAG-3’Choose the correct amino acid sequence.a. Leu-Val-Arg-Cys-His-Glyb. Cys-His-Gly-Thrc. Pro-Trp-His-Leu_Thr*d. Met-Ala-Pro-Asp156. Table 12.1 is a table of codons from your textbook.Using the table above, translate the following mRNA sequence from the start codon to the stop codon (you need to find the translation start codon first): 5’-CCAUGGACGAACGCUGACG-3’Choose the correct amino acid sequence.a. Pro-Trp-Thr-Asn-Ala-Asp*b. Met-Asp-Glu-Argc. Arg-Gln-Arg-Ser-Ser-Metd. His-Gly-Arg-Thr-Leu-Thr157. During polypeptide chain elongation on ribosomes a. a tRNA at the P site transfers the growing polypeptide chain to the tRNA at the A site, and tRNA at the P site is moved to the E site. b. a charged tRNA bearing a single amino acid binds to the A site. c. and after the peptyl transfer reaction is complete, the ribosome moves ahead one codon toward the 3’ end of the mRNA. *d. All of the above 158. In bacterium growth media with both lactose and glucose, which sugar bacteria will use first: a. lactose *b. glucose c. lactose and glucose at the same time d. none of the above 159. In the media in which the bacteria, E. coli, is growing, the presence of lactose ……… (finish the sentence) a. activates the CAP activator by increasing cAMP level. b. activates the CAP activator by decreasing cAMP level. c. increases the binding of lac repressor to the operator of the lac operon. *d. reduces the binding of lac repressor to the operator of the lac operon 160. In the media in which the bacteria, E. coli, is growing, the absence of glucose……… (finish the sentence) *a. activates the CAP activator by increasing cAMP level. b. activates the CAP activator by decreasing cAMP level. c. increases the binding of lac repressor to the operator of the lac operon. d. reduces the binding of lac repressor to the operator of the lac operon 161. If you make a mutation in the lac repressor gene (lac I), what will happen: a. the lac operon will not be expressed *b. the lac operon will be expressed constitutively. c. the lac operon will be expressed only in the presence of lactose d. All of the above 162. If you make a mutation in the lac Operator (Lac O), what will happen: a. the lac operon will not be expressed *b. the lac operon will be expressed constitutively. c. the lac operon will be expressed only in the presence of lactose d. All of the above 163. The promoters of eukaryotic genes include: a. TATA box b. transcription start site c. Regulatory region *d. All of the above 164. The promoter regulatory elements to which activators, a class of transcription factors, bind are called: a. Mediators b. Accelerators *c. Enhancers d. Augmentors e. None of the above165. The initiation of transcription in eukaryotes involves: *a. assembly of preinitiation complex that includes GTFs (General Transcription Factors) and RNA polymerase II. b. assembly preinitiation complex that includes GTFs only. c. assembling preinitiation complex that include RNA polymerase II only. d. None of the above. 166. What are the functions of GTFs (General Transcription Factors): a. bind to core promoter. b. recruit RNA polymerase. c. Melt double strand DNA at the transcriptional start site to initiate transcription *d. All of above 167. Transcription activators: *a. Binds DNA elements in enhancer to activate transcription. b. Mediates interaction between transcription activators and GTFs. c. producing the 5’ cap during mRNA processing. d. splicing out non-coding introns. 168. Coactivator or mediator: a. Binds DNA elements in enhancer to activator transcription. *b. Mediates interactions between transcription activators and GTFs c. producing the 5’ cap during mRNA processing. d. splicing out non-coding introns. 169. How can transcription “activator” change chromatin compaction? a. by recruiting histone acetyl transferase. b. by recruiting chromatin remodeling proteins. *c. by recruiting both histone acetyl transferase and chromatin remodeling proteins. d. None of the above 170. Which is NOT ture about MicroRNA: a. MicroRNA is generated from double stranded RNA by dicer. *b. MicroRNA is usually 30-50 nucleotides in length. c. MicroRNA acts to degrade target mRNA by bringing RISC complex to the target. d. MicroRNAs can inhibit translation. 171. Let us assume that the transition of an insect from the larval stage of development to a pupa is controlled by the expression of a microRNA. Knowing the general function of microRNAs, what might be the possible role of the microRNA in this developmental process? a. Targeting the promoter of a gene required for this developmental process. b. Promoting the assembly of ribosomes needed for this developmental process. c. Enhancing the production of mRNAs required for this developmental process. *d. Degrading a messenger RNA encoding a protein that might interfere with this developmental process.? 172. What the advantage for genes that are regulated at translation initiation step? a. For these genes, they don’t need to transcribe the genes to make mRNAs. b. The mRNAs of these genes form secondary structure so the mRNA is more stable. *c. For these genes, the regulation of protein accumulation happens faster than the genes regulated at transcription level. d. None of the above.173. When an effector molecule binds to a transcription repressor protein, the repressor protein changes shape and is no longer able to bind to DNA. What would happen to the rate of transcription if the concentration of the effector molecules was reduced?a. Increase*b. Decreasec. Remain the same174. You’ve isolated a strain of E. coli which expresses the lac operon even in the absence of lactose. Which of the following events could explain this phenotype?a. A. A mutation in the lacI gene which renders the lac repressor unable to bind DNA.b. B. A mutation in the lacI gene which prevents the lac repressor from binding allolactose.c. C. A mutation in the lac operator which prevents binding by lac repressor.*d. Both A and Ce. None of the above.175. Complete the following: In regulation of the lac operon, the lac repressor protein .....a. Activates lac transcription when it is bound to allolactose.*b. Represses lac transcription when it is not bound to allolactose.c. Binds cAMP and activates transcription.d. Binds cAMP and represses lac transcription.176. Complete the following: In regulation of the lac operon, the Catabolite Activator Protein (CAP) .....a. Binds allolactose and activates lac transcriptionb. Binds allolactose and represses lac transcription*c. Binds cAMP and activates transcription.d. Binds cAMP and represses lac transcription.177. Unlike in prokaryotes, in eukaryotes RNA transcripts are often processed in the following ways:a. Addition of a 5’ cap (a modified G residue).b. Addition of a 3’ polyA tailc. Splicing of exons*d. All of the above.178. How is gene regulation by steroid hormones similar to induction of the E. coli lac operon by lactose?a. A. In both cases a transcription factor is imported into the nucleus.b. B. Both cases involve binding of a small effector molecule to a transcription factor.c. C. Both involve binding of a transcription factor near the gene promoter.*d. B and C only.e. All of the above. 179. In eukaryotes, some genes are regulated at the post-transcriptional level by micro RNAs (miRNAs). Which of the following about miRNAs is NOT true?a. miRNAs are 21 – 22 nucleotides in length.*b. each miRNA is linked to an amino acid by aminoacyl miRNA synthetase.c. miRNAs hybridize to their mRNA targets by complementary base-pairing.d. miRNAs can down-regulate their targets by either inhibiting translation or causing the mRNA to be degraded.Cell Signaling180. Receptors are ________. *a. proteins that change conformation upon interaction with a stimulus b. genes that change expression in response to a stimulus c. phosphorylation cascades? that control cellular responses d. specialized organelles that perceive environmental signals e. all of the above 181. The process by which information from a cell’s environment is perceived and relayed to control a cellular response is known as *a. signal transduction b. chemotaxis c. meiosis d. translation e. impulsive respondus 182. Cell communication ________.a. requires cytoplasmic connections. b. only occurs over short distances. c. controls mitotaxis. d. involves the exchange of genes. *e. coordinates developmental processes in multicellular organisms. 183. Your textbook defines three categories of cell surface receptors that respond to extracellular signals.? They are: a. Ligand-gated ion channels, steroid receptors, G-protein coupled receptors *b. Enzyme-linked receptors, G-protein coupled receptors, ligand-gated ion channels c. Steroid receptors, enzyme-linked receptors, G-protein couple receptors d. Ligand-gated channels, exocrine receptors, G-protein couple receptors e. Exocrine receptors, enzyme-linked receptors, ligand-gated ion channels 184. What is the likely mechanism by which a G-protein coupled receptor might transduce and amplify a signal intracellularly? a. By upregulating the expression of a transporter. *b. By promoting the production of a second messenger. c. By degrading a repressor. 185. What is the likely mechanism by which an enzyme-linked receptor might transduce and amplify a signal intracellularly? *a. By activating a protein kinase cascade. b. By degrading a repressor. c. By upregulating the expression of a transporter.?186. What benefits do hormone signaling provide for a multicellular organism? a. Long distance cellular communication. b. Amplification of weak signals. c. Coordination of bodily functions d. Protection from pathogen attack. e. None of the above *f. All of the above??187. From the graph above showing the amount of ligand bound to the receptor at different ligand concentrations, what do you estimate to be the Kd for ligand/receptor interaction as shown?a. About 1 pM*b. About 5 pMc. About 15 pMd. About 30 pMe. About 60 pM188. If you did another experiment with the same ligand, only this time you add a fixed amount of a weak competitive inhibitor of the ligand along with the ligand, which of the following would be true? Note: You are still measuring the amount of ligand bound while increasing the ligand concentration.a. The Kd will decrease.b. The maximum binding will decrease.*c. The Kd will increase.189. With reference to the above diagram from your textbook.? The G-protein is activated ….finish the sentencea. when theβ/γ dimer associates with the α subunit.b. when ATP concentrations are high enough to activate adenylyl cyclase.*c. by the dissociation of the β/γ dimer from the αsubunit.d. by the exchange of ATP for GTP.e. All of the abovef. None of the above?190. With reference to the above diagram from your textbook.? Epinephrine acts …. (finish the sentence)a. bythe GPCR transducing the signal across the plasma membrane.b. by promoting the dissociation of the G-protein β/γ dimer from the α subunit.c. by producing a second messenger (cyclic adenosine monophosphate).*d. All of the above.e. None of the above.191. In response to unidirectional light …….. (finish the sentence) a. a plant seedling will bend away from the light. b. the hormone auxin will accumulate on the side facing the light. *c. the side facing the light will grow more slowly than the side away from the light. d. the hormone auxin will slow growth on the side of the seedling to which the hormone accumulates. e. All of the above.??192. Indoleacetic acid (IAAH) is an example of an auxin, a plant hormone.? Its chemical structure is depicted in the figure above.? Many plant cells also express an auxin influx carrier protein (pink in the figure).? Why is this carrier protein expressed?a. IAAH cannot cross the membrane without a carrier protein.*b. Depending upon the pH, IAAH may not be able to cross the membrane.c. The carrier protein transports the auxin across the plant cell wall.d. All of the above.193. The localized expression patterns of auxin efflux carrier proteins influence the direction of auxin transport.? These expression patterns are dynamic and change in response to environmental signals.? Would the PIN protein expression pattern in cell A or cell B represent the condition when auxin transport towards the roots needs to be increased?*a. Cell Ab. Cell B194. The figure above illustrates the activation and inactivation of a G protein-coupled receptor.? If a nonhydrolyzable form of GTP, a form that does not loose the terminal phosphate group to form GDP, was added to cells, which of the following would be true?a. The ligand would not bind to the receptor.b. The αβγ subunits of the G protein would not dissociate.*c. Once activated, signaling through the receptor would continue for a longer time than normal.d. None of the abovee. All of the above195. The figure above illustrates signaling through the EGF receptor.? Which of the following would represent a gain-of-function situation for the EGF receptor?a. A mutation in the EGF receptor that binds ligand, but does not allow the receptor to dimerize.b. Deletion of the gene encoding Erkc. Increased cell division due to the inactivation of a tumor suppressor*d. Deletion of the ligand binding domain of the EGF receptor so that it becomes ligand independente. None of the abovef. All of the above196. The figure above illustrates signaling through the EGF receptor.? Which of the following would represent a loss-of-function situation for the EGF receptor?a. A constitutively active from of the Ras protein.b. Deletion of the ligand binding domain of the EGF receptor so that it becomes ligand independent*c. A mutation of the EGF receptor so that it can no longer be phosphorylated.d. All of the abovee. None of the above. 197. You want to test the hypothesis that EGF receptor activation is sufficient for stimulate cell division in cultured epithelial cells.? Which of the following would potentially test your hypothesis?a. A. Forcing expression of the Her2 protein in the cultured cells. The Her2 form of the EGF receptor is constitutively active.b. B. Add epidermal growth factor to the cell culture medium.c. C. Add GDP to the cell culture mediumd. All of the above*e. A and B above198. You want to test the hypothesis that Ca2+ release is necessary to form activated calmodulin.? Which of the following is the best test your hypothesis?a. Add a Ca2+ionophore to the cell culture medium. Ca2+ionophores form Ca2+ permeable channels in cell membranes.b. Inhibit the activity of G protein-coupled receptors*c. Deplete the cells of Ca2+ and then activate phospholipase C leading to IP3 release.199. Which is NOT a hormone found in animals: a. Amine b. peptide *c. auxin d. steroid 200. Which is true about hypothalamus and pituitary: a. Hypothalamus makes neurohormones b. The nurohormones travel to anterior pituitary c. Anterior pituitary can synthesize different hormones to regulate various processes *d. All of the above 201. If Iodine (I) is missing in the diet, what will happen to the thyroid gland: *a. increase in size b. decrease in size c. remain the same d. none of the above 202. In pancreas, two hormones, Insulin and Glucagon, function antagonistically to regulate blood glucose level. Insulin functions to: a. Increase blood glucose level *b. Decrease blood glucose level c. Does not change blood glucose leveld)None of the above 203. In pancreas, two hormones, Insulin and Glucagon, function antagonistically to regulate blood glucose level. Glucagon functions to: *a. Increase blood glucose level b. Decrease blood glucose level c. Does not change blood glucose level d. None of the above ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download