250+ TOP MCQs on Electron-Transfer reactions in Mitochondria and Answers

Biochemistry Assessment Questions and Answers focuses on “Electron-Transfer reactions in Mitochondria”.

1. Protein that contains a nucleic acid derivative of riboflavin is called _________
A. Nucleic acid
B. Amino acid
C. Flavoprotein
D. None
Answer: C
Clarification: Flavoproteins contain a very tightly, sometimes covalently, bound flavin nucleotide, either FMN or FAD.

2. NADP-linked dehydrogenase catalyzes _________
A. Glucose 6-phosphate+NADP+ ↔ 6-phosphogluconate + NADPH + H+
B. Lactate + NAD+ ↔ pyruvate + NADH + H+
C. Pyruvate + CoA + NAD+ ↔ acetyl-CoA + CO2 + NADH + H+
D. L-Malate + NAD+ ↔ oxaloacetate + NADH + H+
Answer: A
Clarification: NADP-linked dehydrogenase catalyzes Glucose 6-phosphate+NADP+ ↔ 6-phosphogluconate + NADPH + H+.

3. A lipid-soluble benzoquinone with a long isoprenoid side chain is?
A. Ubiquinone
B. Cytochrome b
C. Cytochrome c
D. Cytochrome a
Answer: A
Clarification: Ubiquinone also known as coenzyme Q is a lipid-soluble benzoquinone with a long isoprenoid side chain.

4. The only membrane bound enzyme in the citric acid cycle is _________
A. Succinate dehydrogenase
B. NADH dehydrogenase
C. ATP synthase
D. Acyl co-A dehydrogenase
Answer: A
Clarification: The only membrane bound enzyme in the citric acid cycle is succinate dehydrogenase.

5. The first step in the β oxidation of fatty acyl co-A is catalyzed by _________
A. Succinate dehydrogenase
B. NADH dehydrogenase
C. ATP synthase
D. Acyl co-A dehydrogenase
Answer: D
Clarification: It involves the transfer of electrons from the substrate to the FAD of the dehydrogenase, then to ETF.

6. Complex 1 is also called _________
A. NADH dehydrogenase
B. Succinate dehydrogenase
C. Cytochrome bc1 complex
D. Cytochrome oxidase
Answer: A
Clarification: Complex 2 is called succinate dehydrogenase.
Complex 3 is called the cytochrome bc1 complex.
Complex 4 is called cytochrome oxidase.

7. Complex 2 is also called _________
A. NADH dehydrogenase
B. Succinate dehydrogenase
C. Cytochrome bc1 complex
D. Cytochrome oxidase
Answer: B
Clarification: Complex 1 is called NADH dehydrogenase.
Complex 3 is called the cytochrome bc1 complex.
Complex 4 is called cytochrome oxidase.

8. Complex 3 is also called _________
A. NADH dehydrogenase
B. Succinate dehydrogenase
C. Cytochrome bc1 complex
D. Cytochrome oxidase
Answer: C
Clarification: Complex 1 is called NADH dehydrogenase.
Complex 4 is called cytochrome oxidase.
Complex 2 is called succinate dehydrogenase.

9. Complex 4 is also called _________
A. NADH dehydrogenase
B. Succinate dehydrogenase
C. Cytochrome bc1 complex
D. Cytochrome oxidase
Answer: D
Clarification: Complex 1 is called NADH dehydrogenase.
Complex 3 is called the cytochrome bc1 complex.
Complex 2 is called succinate dehydrogenase.

10. In mitochondria, hydride ions are removed from substrates by _________
A. NAD-linked dehydrogenases
B. NADP-linked dehydrogenases
C. ATP synthase
D. Succinate dehydrogenases
Answer: A
Clarification: In cytosol hydride ions are removed from substrates by NADP-linked dehydrogenases.

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