How many carbon dioxide are needed to produced 9 G3P in calvin cycle?

To determine the number of carbon dioxide molecules needed to produce 9 G3P (glyceraldehyde-3-phosphate) molecules in the Calvin cycle, we need to understand the stoichiometry of the process.

In the Calvin cycle, 3 molecules of carbon dioxide combine with 3 molecules of ribulose-1,5-bisphosphate (RuBP) to produce 6 molecules of 3-phosphoglycerate (3PG). This reaction is catalyzed by the enzyme RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase).

Subsequently, 6 molecules of 3PG go through a series of reactions to produce 1 molecule of G3P. Therefore, each G3P molecule requires 2 molecules of 3PG.

Now, since we are given that we need to produce 9 G3P molecules, and each G3P requires 2 molecules of 3PG, we can calculate the total number of 3PG molecules needed:

Total number of 3PG molecules = 9 (G3P) × 2 (3PG per G3P) = 18 3PG

Since each 3PG molecule is formed from each carbon dioxide molecule, the number of carbon dioxide molecules needed to produce 18 3PG molecules is also 18.

Therefore, to produce 9 G3P molecules in the Calvin cycle, 18 carbon dioxide molecules are needed.