Photosynthesis basics: which combination lists all products generated directly by the light reactions (photochemical phase) of photosynthesis?

Introduction / Context:
The light reactions capture solar energy to produce high-energy compounds that power the Calvin–Benson cycle. Knowing exactly what the light reactions generate clarifies how the light-independent reactions are fueled.

Given Data / Assumptions:

• Chloroplast thylakoid membranes host photosystems II and I.
• Water is split (photolysis) at photosystem II, releasing O2.
• ATP is made via photophosphorylation, and NADPH is produced via ferredoxin–NADP+ reductase.

Concept / Approach:
Light energy drives electron flow from water to NADP+, forming NADPH, while the proton gradient across the thylakoid membrane drives ATP synthase to produce ATP. Splitting water produces O2 as a by-product. These are the direct outputs of the photochemical phase.

Step-by-Step Solution:

Verification / Alternative check:
Isolated thylakoid experiments show ATP and NADPH formation upon illumination and oxygen evolution measured with oxygen electrodes.

Why Other Options Are Wrong:
Options listing only one or two of the three products are incomplete. The light reactions produce all three: ATP, NADPH, and O2.

Common Pitfalls:
Confusing products of light reactions with those of the Calvin cycle (e.g., carbohydrate synthesis). Sugars are produced in the dark reactions using ATP and NADPH from the light reactions.

Final Answer:
ATP, NADPH, and O2