midterm1

midterm1 - Chem/Biochem 114B Mid-Term 2008 Chem/Biochem...

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Chem/Biochem 114B Mid-Term 2008 Page 1 Chem/Biochem 114B Midterm Exam 8 February 2008 Exam Version ‘B’— Mark in ‘Test Form’ on Scantron Questions 1-25 Multiple Choice 75 points Questions 26-31 Short Answer 36 points 111 points
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Chem/Biochem 114B Mid-Term 2008 Page 2 Questions 1-25 (3 pts. each): Multiple choice 1. (3 pts.) Consider the following metabolic reaction: Succinyl-CoA + Acetoacetate Acetoacetyl-CoA + Succinate Δ G °' = –1.25 kJ/mol This reaction is: A) favorable under standard conditions. B) not favorable under standard conditions. C) always exergonic and can never proceed in the opposite direction. D) spontaneous as written when [succinate] and [acetoacetyl-CoA] are high. E) None of the above Answer: A 2. Increased levels of epinephrine in the blood will: A) activate adenylate cyclase in liver and muscle cells. B) stimulate glycogen synthesis. C) inhibit glycolysis in the muscle cell. D) stimulate gluconeogenesis in the muscle cell. E) inhibit the formation of cAMP. Answer: A 3. (3pts.) Which of the numbered arrows in the figure to the right points toward a “high-energy” phosphoanhydride bond? N N N N NH 2 CH 2 O OH HO O P O O P O P - O OO O - O - O - 1 2 3 4 5 A) 1 B) 2 C) 3 D) 4 E) 5 Answer: E 4. (3pts.) Which of the following reactions is NOT part of the pentose phosphate pathway? A) Transketolase C 5 C 5 C 3 C 7 + + B) + + C 6 C 3 C 5 C 4 Transketolase C) Transaldolase C 3 C 7 C 6 C 4 + + D) C 5 C 6 C 2 C 9 + + Transketolase E) All of the above. Answer: D 5. (3pts.) In which of the following metabolic conversions is ATP “consumed” during glycolysis? A) 1,3-Bisphosphoglycerate 3-phosphoglycerate B) Glucose glucose-6-phosphate
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Chem/Biochem 114B Mid-Term 2008 Page 3 C) 2-Phosphoglycerate 3-phosphoglycerate D) Fructose-1,6-bisphosphate dihydroxyacetone phosphate + glyceraldehyde-3-phosphate E) Glucose-6-phosphate fructose-6-phosphate Answer: B 6. (3 pts.) Consider the following metabolic reaction: Succinyl-CoA + Acetoacetate Acetoacetyl-CoA + Succinate Δ G °' = –1.25 kJ/mol The Δ G °' for the hydrolysis of Succinyl-CoA is –33.9 kJ/mol. What is the Δ G °' for the hydrolysis of Acetoacetyl-CoA: Acetoacetyl-CoA Acetoacetate + CoA A) –35.2 kJ/mol B) –32.7 kJ/mol C) +32.7 kJ/mol D) +35.2 kJ/mole E) none of the above Answer: B 7. (3pts.) Arsenate ion (AsO 4 -3 ) can substitute for phosphate in the reaction catalyzed by glyceraldehyde-3- phosphate dehydrogenase. The product of that reaction is 1-arseno-3-phosphoglycerate. However, this arseno compound rapidly hydrolyzes in water to yield arsenate and 3-phosphoglycerate. When arsenate is present, how many ATP molecules are produced by glycolysis? CO 2 - C HO H CH 2 OPO 3 -2 AsO 4 -3 H 2 O C OAsO 3 -2 COH CH 2 OPO 3 -2 O H 1-Arseno-3-Phosphoglycerate A) 0 B) 1 C) 2 D) 3 E) 4 Answer: A 8. (3pts.) Avidin, a protein in egg whites, binds biotin very tightly and prevents its absorption in the intestine.
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This note was uploaded on 10/30/2010 for the course CHEM 114B taught by Professor Wang during the Winter '09 term at UCSD.

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midterm1 - Chem/Biochem 114B Mid-Term 2008 Chem/Biochem...

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