Cyclic Electron Transport

Question 1

Differences

Answer 1

Photosystem I can function independently of PS II

Electron transport from PS I to ferredoxin (Fd) is not followed by electron donation of NADP+ reductase
Instead, reduced Fd donates electrons back to PQ
PQ continually reduced and oxidized and moves protons across thylakoid membrane without involvement of PS II

Question 2

Net Result

Answer 2

energy absorbed converted into chemical energy for ATP without oxidation of water or reduction of NADP+ to NADPH

Question 3

Important roles

Answer 3

• reduction of carbon dioxide in Calvin cycle requires more ATP than NADPH, additional ATP provided by cyclic ETC
• energy-requiring rxn in chloroplast dependant on ATP from cyclic ETC