Calvin cycle question

[virtualmaster999]

Hey everyone I have a quick question over the Calvin cycle. So in Ferralis notes it says 6 rounds of the Calvin cycle give one glucose molecule but shouldn't it be 2 rounds, since each round has 3 co2 molecules coming in using 9 atp and 6 nadph? What is the right answer that we should be using for studying or on the dat?

Thanks in advance!


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[DAT Destroyer]

Hey everyone I have a quick question over the Calvin cycle. So in Ferralis notes it says 6 rounds of the Calvin cycle give one glucose molecule but shouldn't it be 2 rounds, since each round has 3 co2 molecules coming in using 9 atp and 6 nadph? What is the right answer that we should be using for studying or on the dat?

Thanks in advance!


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The biochemistry of the Calvin-Benson cycle is quite complex and you do not need to know that much detail for the DAT. However, let's go over what we need to know. The Calvin cycle will make hexoses from CO2 and water, CO2 is our carbon source. A glucose molecule contains 6 carbons thus 6 CO2 molecules and 6 receptor molecules are needed for glucose to be made. Consequently, 6 rounds of the cycle are needed to produce 1 molecule of glucose.

Hope this helps..

 

[FeralisExtremum]

since each round has 3 co2 molecules coming in using 9 atp and 6 nadph?

Hmm...not sure where you got these numbers from. Each individual "round" technically only uses 1 CO2 and 2 NADPH, but we always visualize the Calvin Cycle in 6 cycles at a time to illustrate the formation of a single glucose molecule. This also lets us include the regeneration and carbohydrate synthesis steps in a single image without having to say "btw this individual cycle occurs 6 times before this part can take place".