Question

review the schematic diagram of photosynthesis and the involvement of the chloroplast in this process. which statement below is accurate? a adp ⇌ atp occurs regardless of the presence of solar energy. b atp and nadph are utilized in the stroma to break down water and produce hydrogen ions. c carbon dioxide is critical to the initiation of the light independent reactions occurring in the stroma. d carbon dioxide combines with water in the thylakoid membranes to produce stored chemical energy in the form of atp.

Explanation:

1. In photosynthesis, ADP to ATP conversion (photophosphorylation) requires solar - energy in the light - dependent reactions, so option A is incorrect.
2. Water is broken down in the thylakoid membranes during the light - dependent reactions, not in the stroma using ATP and NADPH, so option B is incorrect.
3. The light - independent reactions (Calvin cycle) in the stroma start with the fixation of carbon dioxide, making carbon dioxide critical for its initiation. So option C is correct.
4. Carbon dioxide is involved in the Calvin cycle in the stroma, not in the thylakoid membranes for ATP production from water, so option D is incorrect.

Answer:

C. Carbon dioxide is critical to the initiation of the light independent reactions occurring in the stroma.