Biology 638 Biochemistry II Exam-1

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1 Biology 638 Biochemistry II Exam-1 Using the following values, answer questions 1-3. ATP + H 2 O ADP + P i ΔG = -30 kj/mol Creatine-phosphate + H 2 O Creatine + P i ΔG = -12 kj/mol ½O 2 + 2H + + 2e - H 2 O ΔE = 0.80 V FAD + 2H + + 2e - FADH 2 ΔE = -0.2 V R = 10.0 J mol -1 K -1 F = kj V -1 T = 300 K ln(x) = 2log(x) In the calculation questions, select the closest one. 1. Creatine kinase catalyzes the following reaction. ATP + creatine ADP + creatine-phosphate The ΔG of the above reaction is kj/mol under the biological standard conditions. a. -40 b. -20 c. -10 d. 20 e ph values of the inside (matrix) and outside (intermembrane space) of mitochondrion are 9 and 5, respectively. The electropotential between the inside and outside is 0.30 V (inside is negative). This electrochemical potential is kj/mol. a. -10 b. -20 c. -30 d. -40 e O 2 is reduced by FADH 2 to H 2 O in a mitochondrion by the following reaction: ½O 2 + FADH 2 H 2 O + FAD If the all oxidation energy produced in the above reaction is utilized to synthesize ATP from ADP + P i, how many ATP would be synthesized from five FADH 2 oxidation under standard biological conditions? a. 5 b. 15 c. 20 d. 25 e. 30 1

2 4. A person s urine contains abnormal level of phenylpyruvate. This person might have degradation problem. a. pyruvate b. Gly c. Phe d. Tyr e. heme The figure below is the glycolysis pathway. Using the figure, answer the following three questions. M5 E1 E2 Glucose E3 E4 M2 M3 M4 E5 M6 E6 Pyruvate E10 M10 E9 E8 E7 M9 M8 M7 5. Which step(s) produce ATP? a. E3, E10 b. E7, E10 c. E6, E9 d. E3, E8 6. step is the major regulation site of glycolysis. a. E3 b. E4 c. E5 d. E1 7. What is M7? a. Dihydroxyacetone phosphate b. 1,3-Bisphosphoglycerate c. 2-Phosphoglycerate d. 3-Phosphoglycerate 8. Glycolysis influences oxygen transport. Select the correct statement. a. Fast glycolysis decreases the HbO 2 concentration. b. Slow glycolysis increases the HbO 2 concentration. c. Hexokinase deficient results in high HbO 2 concentration. d. Pyruvate kinase deficient results in low HbO 2 concentration. e. All of the above. 9. 2PG is converted to PEP because. a. conversion of 2PG to PEP is a large exergonic process to pull the previous reaction 3PG to 2PG b. PEP has a higher energy molecule than 2PG c. conversion of 2PG to pyruvate requires many steps d. conversion of PEP to pyruvate is a large exergonic process to produce an ATP 2

3 10. It is well-known that nitroglycerin works on angina pectoris because. a. it increases the IP 3 level in heart smooth muscle b. it increases the camp level in heart smooth muscle c. it produces NO in heart smooth muscle d. it elevates the Ca 2+ concentration in heart smooth muscle 11. has (have) kinase activity. a. Insulin receptor b. Steroid receptors c. α-adrenoreceptors (phosphoinositide pathway receptors) d. β-adrenoreceptors 12. Caffeine inhibits. a. GTP hydrolysis on G sα b. camp hydrolysis to AMP c. G iα from exchanging its bound GDP for GTP d. GTP hydrolysis on G iα 13. Adenylate cyclase is activated by. a. Ca 2+ b. G qα GTP c. camp d. G sα GTP For question 14 25, select that statement that contains the most significant mistake(s). If none of (a, b, c, d) does not contain significant mistake(s) (i.e. all statements are correct), then select e. None of the above. 14. The followings are some characteristics of ATP molecule. a. Hydrolysis of α-phosphate of ATP produces more energetic than that of γ-phosphate. b. Triphosphate moiety of ATP is relatively unstable because its solvation energy is small. c. Triphosphate moiety of ATP is relatively unstable because its resonance stabilization is small. d. ATP occupies the middle rank of phosphoryl-transfer energy production. 15. The followings are some characteristics seen in a metabolism introduction. a. Phosphoguanidines have a high energy bond. b. Complete hydrolysis of ATP (ATP AMP) produces more than 60 kj/mol under the standard biological condition. c. X-ray irradiation gives damages on bacterial DNA and produces various auxotropic mutant bacteria. d. The nitrogen atoms of heme in mammals are supplied from Gly. 3

4 16. The followings are catalytic functions of enzymes. a. A-phosphorylase catalyzes: A-O-B + P i A-P i + HO-B b. A-kinase catalyzes: A + ATP A-P i + ADP c. G6P F6P is catalyzed by a isomerase, while G6P G1P is by a mustase. d. Alcohol to aldehyde conversion is catalyzed by a dehydrogenase if NAD + is involved in the reaction. 17. The followings are some characteristics of enzymes in glycolysis. a. Glyceraldehyde-3-phosphate dehydrodenase is inhibited by iodoacetate because it has an essential Cys in the active site. b. Phosphoglycerate mutase has a phosphorirated Ser in the active site. c. Phosphoglucose isomerase has two essential amino acid residues, Lys and Glu, in the active site. d. Aldolase has two essential amino acid residues, neutral Lys and negatively charged Tyr, in the active site. e. A large conformational change has been observed in hexokinase during the catalytic reaction. 18. The followings are some characteristics in glycolysis and related enzymes. a. The catalytic rate of triose phosphate isomerase (TIM) is very fast, so that the GAP concentration is properly regulated. b. Alcohol dehydrogenase is a zinc containing protein. c. Pyruvate decarboxylase requires a cofactor NAD +. d. The equilibrium constant, K = [GAP]/[DHAP] is very low because GAP inhibits aldolase. 19. The followings are some characteristics in glycolysis. a. Conversion of pyruvate to lactate regenerates NAD + to continue glycolysis. b. Although the glyceraldehyde 3-phosphate dehydrogenase reaction is an endergonic, it occurs because the following phosphoglycerate kinase reaction is a large exergonic. c. If G6P is not converted to F6P, the aldolase cleavage would give the C 2 and C 4 fragments. d. Glycolysis occurs in cytosol. 20. The followings are some descriptions of hexoses. a. Mannose is phosphorylated by hexokinase. b. Glucose is phosphorylated by hexokinase. c. Galactose is phosphorylated by hexokinase. d. Fructose in muscle is phosphorylated by hexokinase. 4

5 21. The followings are some characteristics in glycolysis. a. The active site of PFK has a Cys because addition of iodoacetate in glycolysis causes accumulation of fructose-1,6-bisphosphate (FBP). b. If enolase is moderately inhibited, the deoxy-hb concentration is increased in blood. c. If TIM is moderately inhibited in glycolysis, the FBP concentration is increased. d. Conversion of one glucose to two pyruvates in glycolysis produces two ATP s and two NADH s. 22. Glycolysis is largely regulated by the following enzyme actions. a. Large conformation change of hexokinase b. Allosteric activation/inactivation of phosphofructokinase c. AMP concentration by adenylate kinase d. Hydrolysis by fructose-1,6-bisphosphatase 23. If adenylate kinase is inhibited in glycolysis,. a. the concentration of AMP will be decreased b. the activity of fructose-1,6-bisphosphatase will be decreased c. the activity of phosphofructokinase will be decreased d. the concentration of ATP will be decreased 24. In α-adrenoreceptor (phosphoinositide pathway receptor) signal transduction pathway, plays an important role. a. phospholipase C b. calmodulin c. G qα d. protein kinase A 25. The signal of epinephrine is naturally reduced by. a. hydrolysis of camp b. separation of protein kinase A (R 2 C 2 R 2 + C 2 ) c. hydrolysis of GTP on G sα d. replacement of GDP with GTP on G iα 5