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[资源] 清华大学生物化学题目

清华大学生物化学题目  详见附件
说明：1. 请选择正确答案，填在适当的横线处（1-30题）或写在答题纸上（31-33题）；
2. 答案可能是一个或多个；
3. 每题的分数在标在了题目后面；
4. 本卷满分为100.

1.  If the G` of the reaction A    B is –12 kJ/mol, which of the following statements are correct? (Note the prime symbol means that a thermodynamic parameter is measured at pH.7.0) (2 points)
A. The reaction will proceed spontaneously from left to right at the given conditions.
B. The reaction will proceed spontaneously from right to left at standard conditions.
C. The equilibrium constant favors the formation of B over the formation of A.
D. The equilibrium constant could be calculated if the initial concentrations of A and B were known.
E. The value of G`o is also negative.
Answer(s): A, D

2. Which of the following statements about ATP and its roles in cells are true? (2 points)
A. The ATP molecule is kinetically unstable and is thus consumed within about one minute following its formation in cells.
B. ATP provides free energy to a thermodynamically unfavorable reactions by group transfer, always donating a Pi to form a covalent intermediate.
C. ATP can be regenerated by coupling with a reaction that releases more free energy than does ATP hydrolysis.
D. A transmembrane proton-motive force can drive ATP synthesis.
E. The active form of ATP is usually in a complex with Mg2+.
Answer(s): C, D, E

3. A common moiety for NADP, NAD, FMN, FAD, and coenzyme A is: (2 points)
A. A pyrimidine ring;
B. A three ring structure;
C. An ADP;
D. A pyranose ring;
E. A triphosphate group.
Answer(s): C

4. If the C-1 carbon of glucose were labeled with 14C, which of the carbon atoms in pyruvate would be labeled after glycolysis? (2 points)
A. The carboxylate carbon;
B. The carbonyl carbon;
C. The methyl carbon.
Answer(s)
5. Which of the following are metabolic products of pyruvate in higher organisms? (2 points)
A. Glycerol
B. Lactic acid
C. Acetone
D. Acetyl-CoA
E. Ethanol
Answer(s): B, D

6. Indicate whether each of the following statements about the pentose phosphate pathway is true (T) or false (F). (5 points)
A. It generates NADH for reductive biosyntheses. F
B. The reactions occur in the cytosol. T
C. Transketolase and transaldolase link this pathway to gluconeogenesis. F
D. It is more active in muscle cells than in fat-storage cells. F
E. It interconverts trioses, tetroses, pentoses, hexoses, and heptoses. T

7. Which of the following statements are correct? The citric acid cycle (2 points)
A. does not exist as such in plants and bacteria, because its functions are performed by the glyoxylate cycle.
B. oxidizes acetyl CoA derived from fatty acid degradation.
C. produces most of the CO2 in anaerobic organisms.
D. provides succinyl CoA for the synthesis of carbohydrates.
E. provides precursors for the synthesis of glutamic and aspartic acids.
Answer(s): B, E

8. Match the cofactors of the pyruvate dehydrogenase complex with their corresponding enzyme components and with their roles in the enzymatic steps that are listed. (5 points)
A. Coenzyme A: 3,7
B. NAD+: 2, 9
C. Thiamine pyrophosphate (TPP): 1, 5
D. FAD: 2, 6
E. Lipoamide: 3, 4,8
(1). Pyruvate dehydrogenase component
(2). Dihydrolipoyl dehydrogenase
(3). Dihydrolipoyl transacetylase
(4). Oxidizes the hydroxylethyl group
(5). Decarboxylates pyruvate
(6). Oxidizes dihydrolipoamide
(7). Accepts the acetyl group from acetyllipoamide
(8). Provides a long, flexible arm that coveys intermediates to different enzyme component.
(9). Oxidizes FADH2.
9. Matching the role in fatty acid oxidation and/or mobilization to the appropriate component listed below. (5 points)
A. Bile salt: 2
B. Serum albumin:5
C. ApoC-II:4
D. Apolipoprotein:3
E. Carnitine:1
(1). Acts as a “carrier” of fatty acids across the inner mitochondrial membrane.
(2). Acts as a biological detergent, disrupting fat globules into small mixed micelles.
(3). Binds and transports triacylglycerols, phospholipids, and cholesterol between organs.
(4). Activates lipoprotein lipase, which cleaves triacylglycerols into their components.
(5). Binds some fatty acids molibized from adipocytes and transports them in the blood to heart and skeletal muscle.

10. Which of the following answers complete the sentence correctly? Surplus dietary amino acids may be converted into (2 points)
A. proteins.
B. Fats.
C. ketone bodies.
D. glucose.
E. a variety of biomolecules for which they are precursors.
Answer(s): A, B, C, D,E
11. Which of the following compounds serves as an acceptor for the amino groups of many amino acids during metabolism? (2 points)
A. Glutamine
B. Asparagine.
C. -ketoglutarate.
D. Oxaloacetate
E. Glutamate
Answer(s):C
12. Match the functions for the coenzymes that are involved in amino acid metabolism. (4 points)
A. Pyridoxal phosphate: (3)
B. Coenzyme B12: (2)
C. Tetrahydrobiopterin: (1)
D. NAD+:  (1)
E. Biotin (4)
Answer:  A decrease in the activity of primase would account for the low rate of DNA replication. DNA replication requires the prior synthesis of RNA primers. Decreased rates of dNTP synthesis would also slow replication.

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