Question

In a plant cell, how many ADP molecules will result from the dark reactions of six carbon dioxide

molecules?

Answer 1

During the dark reactions of photosynthesis for six CO₂ molecules, a total of 18 ATP molecules are consumed, producing 18 ADP molecules as by-products.

Step-by-step explanation:

When six molecules of carbon dioxide (CO₂) enter the Calvin cycle of a plant cell's photosynthesis process, they go through a series of reactions that aim to fix carbon and synthesize glucose. First, during the reduction phase, each CO₂ molecule combined with ribulose biphosphate (RuBP) would result in two molecules of glyceraldehyde-3-phosphate (G₃P), using a total of 12 ATP and 12 NADPH for six CO₂ molecules. However, 10 of these G3P molecules are then used to regenerate RuBP, and this regeneration requires an additional six ATP molecules.

Ultimately, for every CO₂ molecule fixed, one ATP is converted to ADP during the regeneration of RuBP. Therefore, for six molecules of CO₂, a total of 18 ATP is used (12 ATP for reduction and 6 ATP for RuBP regeneration). This results in the formation of 18 molecules of ADP, as each used ATP molecule is converted into one ADP molecule.

In summary, consuming 18 ATP molecules will yield 18 ADP molecules during the dark reactions of six molecules of CO₂.

Answer 2

Six molecules of carbon dioxide produce twelve molecules of glyceraldehyde 3-phosphate. Out of twelve, ten molecules are required to synthesize ribulose bisphosphate by utilizing six molecules of ATP that can bind incoming carbon dioxide and restart the cycle. The hydrolysis of ATP produces six molecules each of ADP and inorganic phosphate.

Step-by-step explanation: