课程名称︰普通生物学乙上 课程性质︰必修 课程教师︰陈俊宏 开课学院：医学院 开课系所︰医学系 考试日期（年月日）︰2007／10／25 考试时限（分钟）：110min 是否需发放奖励金：是 （如未明确表示，则不予发放） 21. The presence of cholesterol in the plasma membranes of some animals A. makes the animal more susceptible to circulatory disorders. B. enables the animal to remove hydrogen atoms from saturated phospholipids. C. enables the membrane to stay fluid more easily when cell temperature drops. D. makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. E. enables the animal to add hydrogen atoms to unsaturated phospholipids. 22. When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured emebrane, the bumps seen on the fractured surface of the membrane are A. cholesterol molecules. B. phospholipids. C. peripheral proteins. D. integral proteins. E. carbohydrates. 23. If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions into the cell, which of the following is most likely not true? A. Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. B. The higher sodium ion concentration outside the cell is the result of an electrogenic pump. C. A substance that blocked sodium ions from binding to the cotransport protein would also block the transport of glucose. D. The sodium ions are moving down their electrochemical gradient. E. Glucose is entering the cell against its concentration gradient. 24. What is the cause of familial hypercholesterolemia? A. defective LDL receptors on the cell membranes. B. a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membrane. C. inhibition of the cholesterol active transport system in red blood cells. D. a general lack of glycolipids in the blood cell membranes. E. poor attachment of the cholesterol to the extracellular matrix of cells. 25. Which of the following processes includes all others? A. transport of an ion down its electrochemical gradient. B. facilitated diffusion. C. diffusion of a solute across a membrane. D. osmosis. E. passive transport. 26. The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following is an important consequence of the first law? A. The energy content of an organism is constant. B. Organisms are unable to transform energy. C. The entropy of an organism decreases with time as the organism grows in complexity. D. Life does not obey the first law of thermodynamics. E. The organism ultimately must obtain all of the necessary enegy for life from its environment. 27. When 10,000 molecules of ATP are hydrolyzed to ADP and Pi in a test tube, about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation? A. Cells are open systems, but a test tube is a closed system. B. Cells convert some of the energy of ATP hydrolysis into other forms of energy besides heat. C. The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. D. Cells are less efficient at heat production than nonliving systems. E. The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. 28. Which of the following statements is true regarding enzyme cooperativity? A. A substrate molecule bound to an active site affects the active site of several subunits. B. A substrate binds to an active site and inhibits cooperation between enzymes in a pathway. C. Several substrate molecules can be catalyzed by the same enzyme. D. A product of a pathway serves as a competitive inhibitor of an early enzyme in the pathway. E. A multi-enzyme complex contains all the enzymes of a metabolic pathway. 29. If an enzyme has been inhibited noncompetitively, A. the ΔG for the reaction it catalyzes will always be negative. B. the active site will be occupied by the inhibitor molecule. C. the inhibitor molecule may be chemically unrelated to the substrate. D. a higher activation energy will be necessary to initiate the reaction. E. increasing the substrate concentration will increase the inhibition. 30. All of the following statetments about glycolysis are true EXCEPT: A. Glycolysis has steps involving oxidation-reduction reactions. B. The enzymes of glycolysis are located inthe sytosol of the cell. C. Glycolysis can operate in the complete absence of O2. D. The end products of glycolysis are CO2 and H2O. E. Glycolysis makes ATP exclusively through substrate-level phosphorylation. 31. All of the following are products or intermediates in glycolysis except A. 1,6-fructose bisphosphate. B. FADH2. C. NADH. D. pyruvate. E. phosphoenolpyruvate. (PEP) 32. All of the following are functions of the citric acid cycle except A. production of ATP. B. production of NADH. C. production of FADH2. D. release of carbon dioxide. E. adding electrons and protons to oxygen to form water. 33. How many reduced dinuleotides would be produced with four turns of the citric acid cycle (TCA cycle) ? A. 1 FADH2 and 4 NADH. B. 2 FADH2 and 8 NADH. C. 4 FADH2 and 12 NADH. D. 1 FAD and 4 NAD+. C. 4 FAD+ and 12 NAD+. 34. Which metabolic process is most closely associated with intracellular membranes? A. substrate-level phosphorylation. B. oxidative phosphorylation. C. glycolysis. D. the citric acid cycle. E. alcohol fermentation. 35. Assume a mitochondrion contains 58 NADH and 19 FADH2. If each of the 77 dinucleotides (58 NADH and 19 FADH2) were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis) ? A. 36. B. 77. C. 173. D. 212. E. 1102. 36. Fuel molecules that can potentially be converted to intermediates of glycolysis and/or the citric acid cycle include A. amino acids and proteins. B. glycerol and fatty acids. C. glucose and sucrose. D. starch and glycogen. E. all of the above. 37. Your younger sister lost 15 pounds of fat on a "low carb" diet. Where did the fat go (how was is lost) ? A. Chemical energy was converted to heat and then released. B. It was released as CO2 and H2O. C. It was converted to ATP, which weighs much less than fat. D. It was broken down to amino acids and eliminated from the body. E. It was converted to urine and eliminated from the body. 38. Where do the Calvin cycle the The Krebs cycle take place? A. thylakoid membrane; mitochondrial matrix. B. chlorophyll molecule; mitochondrial inner membrane. C. cytoplasm surrounding the chloroplast; mitochondrial matrix. D. stroma of the chloroplast; mitochondrial matrix. E. chloroplast inner membrnae; mitochondrial inner membrane. 39. In the thylakoid membranes, what is the main role of the antenna pigment molecules? A. harvest photons and transfer light energy to the reaction-center chlorophyll. B. concentrate photons within the stroma. C. synthesize ATP from ADP and Pi. D. split water and release oxygen to the reaction-center chlorophyll. E. transfer electrons from ferredoxin to NADPH. 40. Some photosynthetic organisms contain chloroplasts that lack photosystem Ⅱ, yet are able to survive. The best way to detect the lack of photosystem Ⅱ in these organisms would be A. to do experiments to generate an action spectrum. B. to test for production of either sucrose or starch. C. to test for CO2 fixation in the dark. D. to determine if they have thylakoids in the chloroplast. E. to test for liberation of O2 in the light. 41. Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A. the splitting of water. B. the absorption of light energy by chlorophyll. C. the synthesis of ATP. D. the reduction of NADP+. E. the flow of electrons from photosystem Ⅱ to photosystem Ⅰ. 42. Which of the following is (are) true of the enzyme "rubisco" ? A. It has an affinity for both O2 and CO2. B. It catalyzes a phosphorylation reaction. C. It participates in the Krebs cycle. D. A and C are true. E. A, B, and C are true. 43. CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they A. fix CO2 into organic acids during the night. B. use photosystem Ⅰ and Ⅱ at night. C. use the enzyme phosphofructokinase, which outcompetes rubisco for CO2. D. fix CO2 into sugars in the bundle sheath cells. E. fix CO2 into pyruvate acid in the mesophyll cells. 44. Photorespiration lowers the efficiency of photosynthesis by preventing the formation of A. RuBP carboxylase molecules. B. carbon dioxide molecules. C. ATP molecules. D. 3-phosphoglycerate molecules. E. ribulose bisphosphate molecules. 45. Which of the following conclusions does not follow from studying the absorption spectrum for chlorophyll a and the action spectrum for phtosynthesis? A. There must be accessory pigments that broaden the spectrum of light that contributes energy. B. The red and blue areas of the spectrum are most effective in driving photosynthesis. C. Chlorophyll owes its color to the absorption of green light. D. Not all wavelengths are equally effective for photosynthesis. E. Chlorophyll a has two absorption peaks. --

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