Question

question 3 (5 points)
light is used in photosystem ii and photosystem i to
a) fix carbon dioxide.
b) power the calvin cycle.
c) make carbon dioxide.
d) excite an electron.

Explanation:

• Option A: Carbon dioxide fixation occurs in the Calvin cycle (light - independent reactions), not directly by light in photosystems I and II.
• Option B: The Calvin cycle is powered by ATP and NADPH produced from the light - dependent reactions (involving photosystems I and II), but light itself does not power the Calvin cycle.
• Option C: Photosynthesis consumes carbon dioxide, it does not produce it.
• Option D: In photosystem II and photosystem I, light energy is used to excite electrons. These excited electrons then move through electron transport chains, which is a key part of the light - dependent reactions of photosynthesis.

Answer:

D) excite an electron