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6.3 outline the main steps of the Calvin cycle as: the production of phosphoglycerate from the combining of carbon dioxide with an acceptor molecule the reduction of phosphoglycerate into glyceraldehyde phosphate in two reactions that use ATP and NADPH produced in the light reactions the regeneration of the initial carbon dioxide

outline the main steps of the Calvin cycle as:

  • the production of phosphoglycerate from the combining of carbon dioxide with an acceptor molecule
  • the reduction of phosphoglycerate into glyceraldehyde phosphate in two reactions that use ATP and NADPH produced in the light reactions
  • the regeneration of the initial carbon dioxide acceptor

CO2 + 5-carbon acceptor → [6-carbon intermediate] → two phosphoglycerate.

3C5 + 3C1    > 3C6 (unstable)    > 6C3.

One of these C3 molecules leaves the cycle and the other five C3 molecules are regenerated to form 3 molecules of the C5 acceptor.

Counting C atoms:

3C x 5 + 3C x 1 = 18C

3C x 1 leaves the cycle = 3C

3C x 5 regenerated = 15C

3CO2 + 9ATP + 6NADPH + water → glyceraldehyde phosphate + 8Pi + 9ADP + 6NADP+.

The ATP and NADPH come from the light dependent reactions, the inorganic phosphate (Pi), the adenosine diphosphate (ADP) and nicotinimide adenosine diphosphate are recycled to the light reactions