Biochemistry Questions and Answers – Biological Oxidation-Reduction Reactions

This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses 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
View Answer

Answer: a
Explanation: 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
View Answer

Answer: b
Explanation: 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
View Answer

Answer: d
Explanation: O2 has the highest redox potential.
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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
View Answer

Answer: d
Explanation: 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
View Answer

Answer: c
Explanation: 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
View Answer

Answer: b
Explanation: 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
View Answer

Answer: c
Explanation: Only oxidation involves loss of electrons.
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8. Gain of electrons can be termed as ___________
a) Metabolism
b) Anabolism
c) Oxidation
d) Reduction
View Answer

Answer: d
Explanation: 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
View Answer

Answer: a
Explanation: Alcohol dehydrogenase catalyzes the first step in the catabolism of ethanol.
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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
View Answer

Answer: a
Explanation: Only Glutamate dehydrogenase can utilize both NAD+ and NADP+ as a coenzyme.

Sanfoundry Global Education & Learning Series – Biochemistry.

To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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