In oxygenic photosynthesis (light reactions plus the Calvin cycle), which of the following is NOT a net product of the overall process?

• A. Glucose (carbohydrate)
• B. Water
• C. Oxygen gas
• D. NADPH

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the overall process of oxygenic photosynthesis, which includes the light reactions and the Calvin cycle. The light reactions convert light energy into chemical energy, producing ATP and NADPH, and release oxygen gas as a byproduct from splitting water.
2. Step 2: Identify the net products of the light reactions: oxygen gas (O\_2), ATP, and NADPH. Oxygen is released as a waste product, while ATP and NADPH are used in the Calvin cycle.
3. Step 3: Examine the Calvin cycle, which uses ATP and NADPH to fix carbon dioxide (CO\_2) into glucose (a carbohydrate). The net product of the Calvin cycle is glucose.
4. Step 4: Recognize that water (H\_2O) is actually consumed during the light reactions (it is split to provide electrons and protons), so it is not a net product but rather a reactant in the overall photosynthesis process.
5. Step 5: Conclude that among the options given, water is NOT a net product of oxygenic photosynthesis, while glucose, oxygen gas, and NADPH are net products or intermediates involved in the process.