Lesson eLearning

In the electron transport chain of chloroplasts, which pigment acts as the primary electron donor to plastoquinone?

medium MCQ 1 mark Class 11 · Biology · Photosynthesis in Higher Plants
  1. Chlorophyll a
  2. Chlorophyll b
  3. Phycobilin
  4. Carotenoid
Answer
Chlorophyll a

The correct answer is Chlorophyll a — Other pigments such as chlorophyll b, phycobilin or carotenoid do not donate electrons directly to plastoquinone.

Step-by-step solution

  1. Identify that plastoquinone accepts electrons from PSII.
  2. Recognize that the reaction centre pigment in PSII is P680, which is a chlorophyll a molecule.
  3. Therefore chlorophyll a is the primary electron donor to plastoquinone.
  4. Other pigments such as chlorophyll b, phycobilin or carotenoid do not donate electrons directly to plastoquinone.
Common mistake: Confusing PSI’s primary donor P700 for PSII’s P680

Concept tested: PSII primary electron donor

Published · How this solution was prepared and checked

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