250+ TOP MCQs on The Central Photochemical Event : Light-Driven Electron Flow and Answers

Biochemistry Questions and Answers for Entrance exams focuses on “The Central Photochemical Event: Light-Driven Electron Flow”.

1. A chlorophyll-like accessory pigment lacking Mg⁺² is ____________
A. Pheophytin
B. Cytochrome c
C. Plastocyanin
D. Ferredoxin
Answer: A
Clarification: Pheophytin is a chlorophyll-like accessory pigment lacking Mg⁺².

2. A soluble Cu-containing electron transfer protein is ____________
A. Pheophytin
B. Cytochrome c
C. Plastocyanin
D. Ferredoxin
Answer: C
Clarification: Plastocyanin is a soluble Cu-containing electron transfer protein.

3. Photosystem II is a ____________
A. Pheophytin-quinone type
B. Ferredoxin type
C. Plastocyanin type
D. Plastocyanin-ferredoxin type
Answer: A
Clarification: Photosystem II is a pheophytin-quinone type of system.

4. Which of the following describes the complete route by which electrons flow H₂O to NADP⁺?
A. Z scheme
B. A scheme
C. B scheme
D. X scheme
Answer: A
Clarification: Z scheme describes the complete route by which electrons flow H₂O to NADP⁺.

5. Plastoquinol formed in PSII is oxidized by ____________
A. Cytochrome b₆f
B. Cytochrome c
C. Cytochrome f
D. Cytochrome h
Answer: A
Clarification: Plastoquinol formed in PSII is oxidized by cytochrome b₆f complex.

6. A mobile, lipid soluble carrier of two electrons present in chloroplasts is ____________
A. PQ_B
B. Q
C. Cytochrome c
D. Plastocyanin
Answer: A
Clarification: Q is present in mitochondria; cytochrome c and plastocyanin are water-soluble protein that carries one electron.

7. A mobile, lipid soluble carrier of two electrons present in mitochondria is ____________
A. PQ_B
B. Q
C. Cytochrome c
D. Plastocyanin
Answer: B
Clarification: PQ_B is present in chloroplasts; cytochrome c and plastocyanin are water-soluble protein that carries one electron.

8. A water-soluble protein that carries one electron present in mitochondria is ____________
A. PQ_B
B. Q
C. Cytochrome c
D. Plastocyanin
Answer: C
Clarification: PQ_B and Q are lipid-soluble protein; plastocyanin is present in chloroplast.

9. A water-soluble protein that carries one electron present in the chloroplast is ____________
A. PQ_B
B. Q
C. Cytochrome c
D. Plastocyanin
Answer: D
Clarification: PQ_B and Q are lipid-soluble protein; cytochrome c is present in mitochondria.

10. Cyanobacteria does not use which of the following for both oxidative and photophosphorylation?
A. Cytochrome c₆
B. Cytochrome b6f
C. Plastoquinone
D. Plastocyanin
Answer: D
Clarification: Cyanobacteria use cytochrome c₆, cytochrome b₆f and plastoquinone for both oxidative and photophosphorylation.

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