1、中国科学技术大学生物化学试卷学号 姓名 分数 Section （50 points）MULTIPLE CHOICE: 1 point each, 1 answer each1. If an unfavorable biochemical reaction is coupled to ATP hydrolysis, the reaction will probably bea) Stopped b) Driven forwardc) Reversed d) Non-spontaneouse) Not affected2. The bonds linking the final two phosp
2、hate residues in ATP contain a lot of energy because they area) Hydrogen bondsb) Peptide bondsc) Phosphodiester bondsd) Phosphoanhydride bondse) glycosidic3. For a step in a reaction pathway to serve as a control point it should be a) Irreversibleb) Endergonicc) Far from equilibriumd) Both a and ce)
3、 All of the above4. The ultimate product of complete oxidation of carbohydrates isa) Carbon dioxideb) Acetyl CoAc) Pyruvated) Acetate ione) NADH5. Phosphofructokinase I deficiency results in:a) An overproduction of Fructose 6-phosphateb) An overproduction of Fructose 1,6-bisphosphatec) Fructose 1,6-
4、bisphosphate deficiencyd) a and c onlye) All of the above6. How many FADH2 and NADH are produced by one round of the oxidation pathway?a) 1 eachb) 1 FADH2 and 2 NADHc) 2 eachd) 2 FADH2 and 1 NADHe) 3 each7. Fats are a more efficient energy source than carbohydrates because they are morea) Oxidizedb)
5、 Polarizedc) Reducedd) All of the abovee) None of the above8. What two 3-carbon molecules are generated by the cleavage of fructose-1,6 bisphosphate in glycolysis?a) Glyceraldehydes-3-phosphate and 3-phosphoglycerateb) Glyceraldehydes-3-phosphate and dihydroxyacetone phosphatec) Pyruvate and phospho
6、enolpyruvated) Enolase and 2-phosphoglyceratee) Glyceraldehydes-3-phosphate and pyruvate9. Which of the following is a ketone bodya) Dihydroxyacetoneb) Acetoacetatec) Fatty acidd) Amino acide) glucose10. Exergonic reactions:a) Release energyb) Are non-spontaneous reactionsc) Do not occur in natured)
7、 Cannot be coupled to endergonic reactionse) None of the aboveSHORT QUESTIONS: 2 points each1. How many ATPs are made from one glucose monomer in glycolysis starting with free glucose that you ingested? 22. How many ATPs are made from one glucose monomer in glycolysis that has been released from sto
8、red glycogen? 33. How many NADH molecules are generated from one glucose monomer in glycolysis? 24. Name the three regulated enzymes in glycolysis.Hexokinase, Phosphofructokinase, or Pyruvate Kinase5. Where does glycolysis occur in the cell? Cytosol 6. If there is no oxygen present in a metabolic sy
9、stem, what is the fate of pyruvate?(i.e. what compound is pyruvate converted to under anaerobic conditions?)In yeast: ethanolIn mammalian systems: lactate7. What is the main function of triacylglycerols?Storage of fat, or energy storage8. Name two of the compounds that are metabolic intermediates ge
10、nerated from the degradation of the carbon skeleton of the 20 fundamental amino acid.Succinyl-CoA, oxaloacetate, or acetyl CoA9. One of the two nitrogen atoms of urea is derived directly from an amino acid. Name the amino acid that directly contributes this nitrogen atom.Aspartate 10. Identify two r
11、eactions in glycolysis that are examples of substrate-level phosphorylation of ADP. (2 points)1. Phosphoglycerate Kinase2. Pyruvate KinaseLONG ANSWER1. Briefly describe the Cori Cycle in mammalian systems. What is/are the purpose(s) of this cycle. (4 points)The Cori cycle operates during exercise, w
12、hen aerobic metabolism in muscle cannot keep up with energy needs. Without oxygen, you cannot regenerate NAD+ from NADH, resulting in lactic acidosis. NADH is reoxidized by the enzyme pyruvate dehydrogenase, which catalyzes pyruvate - lactate in muscle cells. The lactate is then transported to the l
13、iver and undergoes gluconeogenesis and the glucose returned to the muscles.2. Glucose-6-phosphate is a branch point in metabolism and will go down different pathways depending upon cellular conditions. Name the pathway(s) that glucose-6-phosphate will most likely follow under the cellular conditions
14、 listed below? (8 points)(Choose from the following pathways. Note that multiple pathways may apply, not all pathways must be used and pathways may be used more than once.)Glycolysis TCA Cycle GluconeogenesisGlycogen Synthesis Pentose Phosphate Pathway -oxidation1) High levels of cellular ATP and hi
15、gh levels of glucoseGlycogen Synthesis2) cells in damaged heart tissue that is being repaired that have low levels of ATPPentose Phosphate Pathway, Glycolysis, and TCA Cycle3) Low levels of cellular ATPGlycolysis and TCA Cycle4) Need for NADPH but not ATPPentose Phosphate Pathway and Gluconeogenesis
16、3. Compare the following aspects of fatty acid oxidation and synthesis. (8 points)1) Site of the process.Mitochondria vs cytosol2) Acyl carrier.CoA vs acyl carrier protein (ACP)3) Reductants and oxidants.NAD+, FAD vs NADPH4) Organization of the enzyme system.Single enzymes vs multifunctional enzymeS
17、ection （50 points）一、选择题（1 分6）1. 对正在进行光合作用的某一植物，突然 ，可发现其叶肉细胞内 RuBP 的含量立即上升。A停止光照 B降低 CO2浓度 C升高 CO2浓度 D停止光照并降低 CO2浓度2. 下列氧化还原系统中标准氧化还原电位最高的是 。A.延胡索酸/琥珀酸; B. CoQ/CoQH2; C.细胞色素 a(Fe2+/Fe3+); D. 细胞色素 b(Fe2+/Fe3+); E. NAD+/NADH3. 用酵母菌酿酒，理想的方法是 。A先通气后密封 B通足空气C先密封后通气 D尽量密封解析: 酵母菌是兼性呼吸的微生物，有氧呼吸时代谢旺盛，大量繁殖，无氧呼
18、吸时产生酒精。因此，本题应选 A，先通气繁殖到一定量后，再密封发酵，使酒精的产率较高。4.将水果放在地窖中，可贮存较长的时间，其主要原因是 。A温度恒定 B湿度恒定 C黑暗无光 D二氧化碳浓度较高 解析:地窖透气性差，贮藏在里面的水果通过呼吸作用使二氧化碳浓度逐渐上升，氧气含量下降，致使呼吸作用受到抑制，代谢下降，这样有利于保存时间延长。本题应选D。5以下哪个反应场所是正确的： 。BAC0 2 十 H 20 (CH 20) 十 0 2 反应发生在叶绿体基质中（O2 在类囊体的囊腔）B4Fe 3 十 2H 2O 4Fe 2 十 4H 十 O 2 反应发生在类囊体上CPEP 十 HC0 3- OA
19、A 十 Pi 反应发生在叶绿体中（叶肉细胞的胞质）DRuBP 十 0 2 磷酸乙醇酸 十 PGA 反应发生在细胞质中（叶绿体基质）6一棵重 10g 的植物栽在水分、空气、温度、光照均适宜的环境中，一月后重达 20g，增加的质量主要来自： 。DA光照 B空气 C水分 D水分和空气二、填空题（2 分10）1.左图为叶片光合速率对细胞间隙 CO2浓度响应示意图。横坐标上两个点对应浓度分别为 (B) 和(F) ；P m为 ； OA 为 。(CO 2补偿点，CO 2饱和点，最大光合速率，光下叶片向无 CO2气体中的释放速率)2. TCA 循环中有两次脱羧反应，分别是由 和 催化。脱去的 CO2 中的 C
20、 原子分别来自 中的 和 。 （异柠檬酸脱氢酶，a酮戊二酸脱氢酶, 草酰乙酸，C1, C4）3. 乙醛酸循环中不同于 TCA 循环的两个关键酶是 和 。 （异柠檬酸裂解酶，苹果酸合成酶）4. 三羧酸循环是 1937 英国生物化学 首先发现的。HKrebs 5. TCA 循环中的大多数酶位于 ，只有 位于线粒体内膜。 （线粒体基质，琥珀酸脱氢酶）6. 根据植物碳同化过程中最初产物所含碳原子的数目以及碳代谢的特点，可将碳同化途径分为 途径、 途径和 途径三种类型。 （C 3，C 4，景天科酸代谢）7. 糖酵解产生的 NADHH+ 必需依靠 系统和 系统才能进入线粒体，分别转变为线粒体中的 和 。
21、（甘油磷酸穿梭，苹果酸天冬氨酸穿梭，FADH2，NADH）8. TCA 循环发生在 中，是需氧生物体内的多种物质的代谢枢纽 ;PPP 途径是在 内进行的， 乙醛酸途径发生在植物和微生物的 中。 （线粒体的基质，细胞质，乙醛酸体）9绿色植物和光合细菌都能利用光能将 合成有机物，它们都属于光养生物。从广义上讲，所谓光合作用，是指光养生物利用 把 合成有机物的过程。 （CO ，光能，CO ）101954 年美国科学家 D.I.Arnon 等在给叶绿体照光时发现，当向体系中供给无机磷、ADP 和 NADP 时，体系中就会有 和 两种高能物质的产生。同时发现，只要供给了这两种高能物质，即使在黑暗中，叶绿
22、体也可将 转变为糖。所以这两种高能物质被称为“ ” 。(ATP，NADPH，CO 2，同化力)三、问答题 ( 4 分 6)1. What is the effect of each of the following inhibitors on electron transport and ATP formation by the respiratory chain?(a)Azide 叠氮化物(b)Retenone 鱼藤酮(c)DNP(d)Carbon monoxide(e)Antimycin A 抗霉素 A (a)Azide blocks electron transport and prot
23、on pumping at site 3(b)Retenone blocks electron transport and proton pumping at site 1(c)DNP blocks ATP synthesis without inhibiting electron transport by dissipating the proton gradient.(d)Carbon monoxide blocks electron transport and proton pumping at site 3(e)Antimycin A blocks electron transport
24、 and proton pumping at site 22. Glucose labeled with 14C at C-6 is added to a solution containing the enzymes and cofactors of the oxidative branch of the pentose phosphate pathway. What is the fate of the radioactive lable during oxidative phase?The lable emerges at C-5 of ribulose 5-phosphate3. An
25、 illuminated suspension of chlorella is actively carrying out photosynthesis. Suppose that the light is suddenly switched off. How would the levels of 3-phosphoglycerate(3-磷酸甘油酸) and ribulose 1,5-bisphophateduring(RuBP) the next time?The concentration of 3-phosphoglycerate would increase, whereas th
26、e ribulose 1,5-bisphophateduring would decrease.4下图为贾格道夫(Jagendorf 1963)等进行酸-碱磷酸化实验的示意图。在暗中把叶绿体的类囊体放在 pH4 的弱酸性溶液中平衡，让类囊体膜腔的 pH 下降至 4，然后加进 pH8 和含有 ADP 和 Pi 的缓冲溶液，结果生成 ATP。问这一实验有什么科学意义？答：这一实验的实质是要回答这样一个问题，在不照光，没有电子传递的情况下，人为瞬间改变类囊体膜内外 pH 值，使类囊体膜内外之间产生一个 H 梯度是否能使 ADP 与 Pi生成 ATP。这一实验结果证实了在不照光，没有电子传递的情况下，
27、只要类囊体膜内外的有质子梯度就能驱动 ATP 合成。而光照下类囊体内外的 pH 差在活体中正是由光合电子传递和 H 转运所形成的。这一酸碱磷酸化实验给化学渗透假说以最重要的支持证据。5. What is the yield of ATP when each of the following substrates is completely oxidized to CO2 by a mammalian cell homogenate（动物细胞匀浆） ， Assume that glycolysis, the citric acid cycle, and oxidative phosphoryla
28、tion are fully active.(a)Pyruvate(b)Glucose(c)Acetyl-CoA(d)Pyruvate 12.5ATP(e)Glucose 30-32ATP(f)Acetyl-CoA 10ATP6 用温室栽培蔬菜，昼夜温度都保持 25的恒温是否合适？应如何控制温度？答：昼夜温度都保持 25的恒温并不合适，因为 25左右是一般植物生长的最适温度，光合作用和呼吸作用都比较强。到了夜晚，光合作用停止，而在这样的温度下旺盛的呼吸消耗大量的有机物，积累的就比较少了，也即净同化率比较低。正确的方法是：白天维持 25左右，晚上应适当降低温室的温度。新疆的瓜果大又甜、青海的小麦千粒重高，与当地气候特点昼夜温差大有直接关系。
