Biochemistry Multiple Choice Questions on “Biological Oxidation-Reduction Reactions”.
1. Which of the following statements about redox potential is false?
A. NADH/NAD+ redox pair has the least redox potential
B. Oxygen/H2O redox pair has the highest redox potential
C. The components of the electron transport chain are organized in terms of their redox potential
D. The redox potential of a system is usually compared with the potential of the hydrogen electrode
Answer: A
Clarification: NAD+/NADH redox pair has the least redox potential.
2. Which out of the following is not a flavoprotein?
A. Succinate dehydrogenase
B. Cytochrome c
C. Xanthine oxidase
D. NADH dehydrogenase-Qreductase
Answer: B
Clarification: Cytochrome c is not a flavoprotein. Flavoproteins involve in oxidation reactions where loss of electrons takes place but cytochrome c accepts electrons.
3. Which out of the following has the highest redox potential?
A. NAD
B. FMN
C. FAD
D. O2
Answer: D
Clarification: O2 has the highest redox potential.
4. Which one out of the following is not a NAD+ requiring enzyme?
A. Lactate dehydrogenase
B. Pyruvate dehydrogenase complex
C. Maltate dehydrogenase
D. Acyl co-A dehydrogenase
Answer: D
Clarification: Acyl co-A dehydrogenase is not a NAD+ requiring enzyme.
5. Which of the following enzyme catalyses the direct transfer and incorporation of O2 into a substrate molecule is
A. Reductase
B. Oxidase
C. Oxygenase
D. Peroxidase
Answer: C
Clarification: Oxygenase catalyses the direct transfer and incorporation of O2 into a substrate molecule.
6. Which of the following statements is incorrect about oxidase?
A. They catalyze reactions involving hydrogen peroxide
B. They catalyze reaction using O2 as a hydrogen acceptor
C. They catalyze reactions using niacin as a coenzyme
D. They catalyze reactions of direct incorporation of O2 into the substrate
Answer: B
Clarification: They catalyze reactions involving hydrogen peroxide, reactions using niacin as coenzyme and reactions of direct incorporation of O2 into the substrate.
7. Loss of electrons can be termed as ______________
A. Metabolism
B. Anabolism
C. Oxidation
D. Reduction
Answer: C
Clarification: Only oxidation involves loss of electrons.
8. Gain of electrons can be termed as ___________
A. Metabolism
B. Anabolism
C. Oxidation
D. Reduction
Answer: D
Clarification: Only reduction involves the gain of electrons.
9. Which of the following enzyme catalyzes the first step in the catabolism of ethanol?
A. Alcohol dehydrogenase
B. Lactate dehydrogenase
C. Glutamate dehydrogenase
D. Malate dehydrogenase
Answer: A
Clarification: Alcohol dehydrogenase catalyzes the first step in the catabolism of ethanol.
10. Which out of the following enzymes can utilize both NAD+ and NADP+ as a coenzyme?
A. Glutamate dehydrogenase
B. Alcohol dehydrogenase
C. Aldehyde dehydrogenase
D. Glycerol-3-P dehydrogenase
Answer: A
Clarification: Only Glutamate dehydrogenase can utilize both NAD+ and NADP+ as a coenzyme.
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