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NEET2008BotanyPhotosynthesis in Higher PlantsActual

Assertion : The higher concentration of ( O ₂ ) in the atmosphere is inhibitory to photosynthesis. Reason : ( CO ₂ ) is the main substrate of photosynthesis.

Options

  1. AIf both assertion and reason are true and reason is the correct explanation of assertion
  2. BIf both assertion and reason are true but reason is not the correct explanation of assertion
  3. CIf assertion is true but reason is false
  4. DIf both assertion and reason are false.

Correct answer

B. If both assertion and reason are true but reason is not the correct explanation of assertion

Step-by-step solution

Oxygen accumulation causes substantial inhibition of photosynthesis. Both oxygen evolution and CO ₂ assimilation were reduced in the presence of atmospheric oxygen. Oxygen causes a direct and indeed competitive inhibition of Ribulose diphosphate carboxylase. As a result glycolate synthesis is enhanced and leads to begin photorespiration. Carbon dioxide being one of the raw materials for photosynthesis, its concentration affects the rate of photosynthesis markedly. Because of its very low concentration in atmosphere

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