To synthesize one glucose molecule, the Calvin cycle uses _________ molecules of CO2, _________ molecules of ATP, and _________ molecules of NADPH.

Verified step by step guidance

1. Identify the number of CO2 molecules required: In the Calvin cycle, each CO2 molecule is fixed to eventually form a glucose molecule. Since glucose (C6H12O6) has six carbon atoms, you need six CO2 molecules, as each CO2 contributes one carbon atom.
2. Calculate the ATP requirement: For each CO2 molecule fixed, the Calvin cycle consumes 3 ATP molecules. Therefore, multiply the number of CO2 molecules by 3 to find the total ATP molecules used.
3. Determine the NADPH requirement: Similar to ATP, each CO2 molecule fixed requires 2 NADPH molecules. Multiply the number of CO2 molecules by 2 to calculate the total NADPH molecules needed.
4. Summarize the total molecules used: Add up the total molecules of CO2, ATP, and NADPH calculated in the previous steps to get the overall consumption for synthesizing one glucose molecule.
5. Review the stoichiometry of the Calvin cycle to ensure the calculated numbers of CO2, ATP, and NADPH are consistent with the biochemical pathway of glucose synthesis in photosynthesis.

Key Concepts

Calvin Cycle

The Calvin cycle is a series of biochemical reactions that occur in the stroma of chloroplasts in photosynthetic organisms. It is responsible for converting carbon dioxide and other compounds into glucose, using energy derived from ATP and NADPH produced in the light-dependent reactions of photosynthesis. The cycle involves three main phases: carbon fixation, reduction, and regeneration of ribulose bisphosphate.

Carbon Dioxide (CO2) Fixation

In the Calvin cycle, carbon dioxide is fixed into an organic molecule through a reaction with ribulose bisphosphate (RuBP), catalyzed by the enzyme RuBisCO. This process is crucial for synthesizing glucose, as it incorporates atmospheric CO2 into the cycle, ultimately leading to the production of carbohydrates. For every glucose molecule synthesized, six CO2 molecules are required.

Energy Molecules: ATP and NADPH

ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate) are essential energy carriers produced during the light-dependent reactions of photosynthesis. ATP provides the energy needed for various reactions in the Calvin cycle, while NADPH serves as a reducing agent, donating electrons to help convert 3-phosphoglycerate into glyceraldehyde-3-phosphate, a precursor to glucose. The synthesis of one glucose molecule requires a total of 18 ATP and 12 NADPH.