BioInteractive Light Reactions of Photosynthesis 3

Question 1

What is cyclic electron flow in photosynthesis?

Accepted Answer

Electrons from Photosystem I cycle back to the cytochrome b6f complex to generate extra ATP

Answer

Electrons flow only through Photosystem II

Answer

Electrons reduce CO2 directly

Answer

Electrons split water molecules

Question 2

Which molecule connects the two photosystems by carrying electrons from PSI to PSII?

Accepted Answer

Plastocyanin

Answer

Ferredoxin

Answer

Plastoquinone

Answer

NADPH

Question 3

What drives the rotation of ATP synthase in chloroplasts?

Accepted Answer

Flow of H+ ions from thylakoid lumen to stroma

Answer

Flow of electrons

Answer

Absorption of light

Answer

Splitting of water

Question 4

What is the correct sequence of electron flow in the non-cyclic light reactions?

Accepted Answer

H2O → PSII → PQ → Cyt b6f → PC → PSI → Fd → NADPH

Answer

NADPH → PSI → PQ → PSII → H2O

Answer

CO2 → PSI → PSII → NADPH

Answer

H2O → PSI → PSII → NADPH

Question 5

What is the primary pigment in Photosystem II reaction centers?

Accepted Answer

Chlorophyll a (P680)

Answer

Chlorophyll b

Answer

Beta-carotene

Answer

Xanthophyll

Question 6

Why is the thylakoid membrane's extensive surface area important for the light reactions?

Accepted Answer

It maximizes the number of photosystems and electron carriers available

Answer

It stores glucose

Answer

It absorbs CO2

Answer

It houses the Calvin cycle enzymes