For every three CO2 fixed, how many G3P molecules exit the cycle to form sugars?

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Multiple Choice

For every three CO2 fixed, how many G3P molecules exit the cycle to form sugars?

Explanation:
In the Calvin cycle, carbon fixation funnels carbon into three-carbon sugar phosphates, but only a small portion actually leaves the cycle to become sugars. For every trio of CO2 fixed, six molecules of 3-PGA are produced and then reduced to six G3P. However, most of that G3P is used to regenerate the five-carbon RuBP so the cycle can continue. Only one G3P molecule exits the cycle to be used for sugar synthesis. Since two G3P are needed to make one glucose, this exiting G3P per three CO2 is what links CO2 fixation to sugar production.

In the Calvin cycle, carbon fixation funnels carbon into three-carbon sugar phosphates, but only a small portion actually leaves the cycle to become sugars. For every trio of CO2 fixed, six molecules of 3-PGA are produced and then reduced to six G3P. However, most of that G3P is used to regenerate the five-carbon RuBP so the cycle can continue. Only one G3P molecule exits the cycle to be used for sugar synthesis. Since two G3P are needed to make one glucose, this exiting G3P per three CO2 is what links CO2 fixation to sugar production.

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