21. During the light-dependent reactions of photosynthesis, which of the following does not occur?

A. Splitting of water
B. Carbon dioxide fixation
C. Release of oxygen
D. Absorption of light energy by photosystems

22. Which of the following structures or processes are logically associated with chloroplasts?

A. Plant cells
B. Chlorophyll
C. Thylakoid membranes
D. All of these

23. In oxygenic photosynthesis, water is split in order to provide the

A. electrons needed to reduce P680
B. O₂ needed for the dark reactions
C. electrons needed to reduce NADH
D. electrons needed for cyclic photophosphorylation

24. Where do the protons come from that make up the proton gradient used in the light reactions of photosynthesis?

A. Glucose
B. ATP
C. H₂O
D. NADPH

25. Oxidative phosphorylation is to respiration as __________ is to photosynthesis

A. carbon fixation
B. electron transport chain
C. light capture by chlorophyll
D. reduction of NADPH