What are the inputs and outputs of the Calvin cycle?

• A. Inputs: CO2, ATP, NADPH; Outputs: glyceraldehyde-3-phosphate (G3P) and glucose precursors.
• B. Inputs: CO2, ATP; Outputs: ATP.
• C. Inputs: CO2, NADPH; Outputs: glucose.
• D. Inputs: CO2; Outputs: G3P.

Answer: (A)

The Calvin cycle uses carbon dioxide and energy from the light reactions to assemble sugars. The essential inputs are carbon dioxide, ATP, and NADPH. ATP provides the energy to drive the carbon fixation and the conversion steps, while NADPH donates the reducing power to reduce fixed carbon.

The main immediate product from a single turn is glyceraldehyde-3-phosphate (G3P), a three-carbon sugar phosphate that can be used to synthesize glucose and other carbohydrate precursors. Glucose itself isn’t produced in one round; it requires multiple turns to build up enough G3P and then combine or channel those molecules into longer sugars. So the correct description is inputs of CO2, ATP, and NADPH, with outputs including G3P and other glucose precursors.