Question

1. what role does oxygen play in the electron transport chain? a. it is converted into atp. b. it transports pyruvate into the mitochondrion. c. it combines with electrons and hydrogen ions to form water. d. it breaks down glucose into pyruvate. 13. in which part of the chloroplast do light - dependent reactions occur? a. mitochondrial membranes b. stroma c. thylakoid membranes d. cytoplasm 14. how is the energy from sunlight used in the light - dependent reactions? a. it synthesizes glucose directly from water. b. it splits carbon dioxide into oxygen and carbon. c. it converts glucose into oxygen. d. it excites electrons in chlorophyll, which then generate atp and nadph.

Explanation:

1. In the electron - transport chain, oxygen acts as the final electron acceptor. It combines with electrons and hydrogen ions to form water.
2. Light - dependent reactions in chloroplasts occur in the thylakoid membranes where photosystems and electron - transport chain components are located.
3. In light - dependent reactions, sunlight energy excites electrons in chlorophyll. This excitation leads to the generation of ATP and NADPH through electron - transport and chemiosmosis.

Answer:

1. C. It combines with electrons and hydrogen ions to form water.
2. C. Thylakoid membranes
3. D. It excites electrons in chlorophyll, which then generate ATP and NADPH.