Which of the following molecules are required as inputs for the Calvin cycle during photosynthesis?

• A. CO\(_2\), ATP, and NADPH
• B. Glucose, NADH, and CO\(_2\)
• C. Pyruvate, NADPH, and O\(_2\)
• D. O\(_2\), ATP, and FADH\(_2\)

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the Calvin cycle, which is the light-independent reaction of photosynthesis. It occurs in the stroma of chloroplasts and is responsible for synthesizing glucose from carbon dioxide (CO\(_2\)).
2. Step 2: Identify the key inputs required for the Calvin cycle. These include CO\(_2\), ATP, and NADPH. CO\(_2\) provides the carbon atoms for glucose synthesis, ATP supplies energy, and NADPH provides reducing power (electrons).
3. Step 3: Analyze the options provided in the question. Compare each set of molecules to the known inputs of the Calvin cycle: CO\(_2\), ATP, and NADPH.
4. Step 4: Eliminate incorrect options by checking if they include molecules not involved in the Calvin cycle. For example, glucose is a product, not an input; NADH and FADH\(_2\) are used in cellular respiration, not photosynthesis; pyruvate is part of glycolysis, and O\(_2\) is involved in the electron transport chain, not the Calvin cycle.
5. Step 5: Select the correct answer, which is the option containing CO\(_2\), ATP, and NADPH, as these are the required inputs for the Calvin cycle during photosynthesis.