BioInteractive Light Reactions of Photosynthesis 2

Question 1

What process uses the proton gradient across the thylakoid membrane to synthesize ATP?

Accepted Answer

Chemiosmosis

Answer

Chemiosmosis drives ATP synthase using the H+ gradient built up across the thylakoid membrane.

Question 2

Which complex in the thylakoid membrane splits water and releases O2?

Accepted Answer

Oxygen-evolving complex

Answer

The oxygen-evolving complex (OEC) at Photosystem II catalyzes the splitting of water.

Question 3

What happens to electrons after they leave Photosystem II?

Accepted Answer

They pass through the electron transport chain to Photosystem I

Answer

Electrons flow from Photosystem II through the cytochrome b6f complex and plastocyanin to Photosystem I.

Question 4

What role does plastoquinone play in the light reactions?

Accepted Answer

Electron carrier between Photosystem II and cytochrome b6f

Answer

Plastoquinone shuttles electrons and protons from Photosystem II to the cytochrome b6f complex.

Question 5

What is the function of ferredoxin in the light reactions?

Accepted Answer

Transfer electrons from Photosystem I to NADP+ reductase

Answer

Ferredoxin accepts electrons from Photosystem I and passes them to NADP+ reductase to reduce NADP+ to NADPH.

BioInteractive - Photosynthesis BioInteractive Test Practice Test