Question

how are the dark reactions that occur in plants dependent on the light reactions?
a. the chemical energy used in the dark reactions is produced in the light reactions.
b. the light reactions produce the oxygen necessary for the dark reactions to proceed.
c. light energy absorbed during the light reactions is used directly in the dark reactions.
d. during the light reactions, carbon dioxide is converted to sugars, which are used during the dark reactions.
please select the best answer from the choices provided
a
b
c
d

Explanation:

• In photosynthesis, the light reactions produce ATP and NADPH (chemical energy). The dark reactions (Calvin cycle) use these energy - rich molecules (ATP and NADPH) to fix carbon dioxide into sugars.
• Option b: Oxygen is a by - product of the light reactions and is not necessary for the dark reactions. The dark reactions are a series of enzyme - catalyzed reactions that do not require oxygen.
• Option c: Light energy is not directly used in the dark reactions. The dark reactions use the chemical energy (ATP and NADPH) produced in the light reactions.
• Option d: Carbon dioxide is converted to sugars in the dark reactions (Calvin cycle), not in the light reactions. The light reactions are mainly about capturing light energy and producing ATP and NADPH.

Answer:

A. The chemical energy used in the dark reactions is produced in the light reactions.