پنجشنبه 21 اردیبهشت 1391 09:33 ق.ظ
What is obvious from that is the "connection" to the light reactions. The Calvin cycle needs NADPH and ATP from the light reactions. Thus the Calvin cycle is inseparable from the light reactions...they only occur in the light! This is why "dark reactions" is a poor name for the Calvin cycle. This relationship with the light reactions is reciprocal...the light reactions need a supply of ADP, Pi, and NADP+ which come directly from the Calvin cycle:
The Calvin cycle occurs in the stroma
With this knowledge, it is no surprise where the Calvin cycle takes place in a cell. Clearly the need for ATP and NADPH will put the Calvin cycle on the stroma side of the thylakoid membrane where these high-energy molecules are produced by the light reactions. The chemical reactions converting carbon dioxide to carbohydrate are enzymatic rather than electronic, so they are not associated with the thylakoid itself. Rather the Calvin cycle enzymes are dissolved in the stroma (the cytosol of the ancient endosymbiont).
The Calvin cycle is an enzymatic pathway
The enzymes that participate in the Calvin cycle form a cyclic pathway that perpetuates its own raw materials through multiple iterations of the cycle. The pathway is summarized in an overview:
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