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NEETBotanyPhotosynthesis in Higher Plants

What is the most crucial step of the Calvin cycle?

Options

  1. AReduction
  2. BRegeneration
  3. CCarboxylation
  4. DPhosphorylation

Correct answer

C. Carboxylation

Step-by-step solution

Carboxylation is the fixation of CO2 into a stable organic intermediate. Carboxylation is the most crucial step of the Calvin cycle where CO2 is utilised for the carboxylation of RuBP. This reaction is catalysed by the enzyme RuBP carboxylase which results in the formation of two molecules of 3-PGA. Since this enzyme also has an oxygenation activity it would be more correct to call it RuBP carboxylase-oxygenase or RuBisCO.

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