Question :
11.Which statement concerning the stages of catabolism FALSE?
A) The primary : 1318525
11.Which statement concerning the stages of catabolism is FALSE?
A) The primary function of digestion is to break down large food molecules into smaller ones that can be absorbed by the blood.
B) The primary function of Stage II is to produce NADH and FADH2 for the citric acid cycle.
C) Most food molecules enter Stage III of catabolism in the form of acetyl CoA.
D) The primary function of the citric acid cycle in Stage III is to oxidize acetyl groups to CO2, and provide reduced coenzymes for the synthesis of ATP.
E) The primary function of electron transport and oxidative phosphorylation is to oxidize NADH and FADH2, and provide energy for the production of ATP
12.What is the source of energy for the synthesis of ATP in oxidative phosphorylation?
A) O2
B) H+ flowing through ATP synthase
C) ADP
D) inorganic phosphate ions
E) hydrolysis of acetyl CoA
13.In the final step of the citric acid cycle, malate dehydrogenase reduces NAD+ to NADH. Into what product is malate converted in this reaction?
A) citrate
B) fumarate
C) oxaloacetate
D) acetyl CoA
E) ATP
14.Which of the following best describes the function of NAD+ and FAD in catabolic pathways?
A) competitive inhibitors of the enzymes present in each pathway
B) oxidizing agents that accept electrons and hydrogen ions from compounds undergoing oxidation
C) non-competitive inhibitors of the enzymes present in each pathway
D) transport molecules that carry two-carbon acetyl units to or from the different pathways
E) enzymes that catalyze the hydrolysis of ATP
15.Which statement concerning regulation of the citric acid cycle is true?
A) High levels of ATP inhibit the reactions of the cycle.
B) High levels of NADH inhibit the reactions of the cycle
C) Low levels of ATP stimulate the reactions of the cycle.
D) High levels of ADP stimulate the reactions of the cycle.
E) All of the statements are true.
16.What molecule acts as a positive allosteric effector of the conversion of isocitrate to ?-ketoglutarate in the citric acid cycle?
A) NADH
B) ATP
C) ADP
D) CO2
E) O2
17.What is the primary function of electron transport and oxidative phosphorylation?
A) to provide electrons for the hydrolysis of ATP
B) to synthesize the reduced coenzymes NADH and FADH2 that are necessary for digestion
C) to transport electrons and energy from ATP to ADP
D) to oxidize the reduced coenzymes NADH and FADH2, and provide energy for the synthesis of ATP
E) to oxidize food molecules to acetyl CoA and prepare them for entry into the citric acid cycle
18.FADH2 is a less powerful reducing agent (electron donor) than NADH. What is the consequence of this in oxidative phosphorylation?
A) FADH2 requires more steps than NADH does in electron transport to become oxidized.
B) The electrons from FADH2 enter electron transport at a higher energy level than the electrons from NADH.
C) A molecule of FADH2 is only capable of producing 2 molecules of ATP, while a molecule of NADH is capable of producing 3 molecules of ATP.
D) Oxidation of FADH2 occurs in the cytoplasm of the cell, while oxidation of NADH occurs in the mitochondria.
E) FADH2 can only donate 1 phosphate group to ATP, while NADH can donate 2 phosphate groups to ATP.
19.What is the role of F0 in the F0F1 complex used in oxidative phosphorylation?
A) It accepts two electrons and a hydrogen ion from NADH in forming NAD+.
B) It accepts two electrons and two hydrogen ions from FADH2 in forming FAD.
C) It pumps H+ out of the mitochondrial matrix into the intermembrane space.
D) It provides the channel for the return of H+ to the matrix of the mitochondria.
E) It uses the energy released from the flow of H+ to the matrix to synthesize ATP.
20.When amino acids undergo degradation in the liver, what is the first step of the process?
A) decarboxylation
B) removal of the ?-amino group
C) removal of the side chain R group
D) attachment to coenzyme A
E) C-C bond cleavage
