Question

which of these does not describe what is happening in the light - dependent reaction?
a products include atp and nadph.
b reactants include carbon dioxide and water.
c water is broken down and oxygen is produced.
d energy from sunlight is absorbed by chlorophyll.

Explanation:

In light - dependent reactions of photosynthesis:

• Option A: ATP and NADPH are produced (these are energy - carrying molecules for the light - independent stage), so this describes the light - dependent reaction.
• Option B: Carbon dioxide and water are reactants of the light - independent (Calvin cycle) reactions, not the light - dependent reactions. The reactants of light - dependent reactions are light energy, water, and ADP + Pi (for ATP synthesis) and NADP⁺ (for NADPH synthesis).
• Option C: Water is split (photolysis) in light - dependent reactions, and oxygen is released as a by - product, so this describes the light - dependent reaction.
• Option D: Chlorophyll absorbs light energy from the sun, which is used to drive the light - dependent reactions, so this describes the light - dependent reaction.

Answer:

B. Reactants include carbon dioxide and water.