What is the primary product of cyclic electron transport?

Prepare for the Foundations of Biology Exam 1. Dive into key biological concepts with multiple choice questions, hints, and explanations. Ace the exam with our efficient study methods!

Multiple Choice

What is the primary product of cyclic electron transport?

Cyclic electron transport around photosystem I primarily makes ATP. In this pathway, electrons are funneled back into the electron transport chain after PSI, cycling through ferredoxin, plastoquinone, and the cytochrome b6f complex. This flow pumps protons across the thylakoid membrane, creating a proton gradient that drives ATP synthase to produce ATP. Because electrons do not reach NADP+ and the process does not involve water splitting at photosystem II, no NADPH is formed and no oxygen is released. This mechanism mainly serves to supply ATP to balance the energy needs of the chloroplast, especially when more ATP is required than NADPH for the Calvin cycle.

Cyclic electron transport around photosystem I primarily makes ATP. In this pathway, electrons are funneled back into the electron transport chain after PSI, cycling through ferredoxin, plastoquinone, and the cytochrome b6f complex. This flow pumps protons across the thylakoid membrane, creating a proton gradient that drives ATP synthase to produce ATP. Because electrons do not reach NADP+ and the process does not involve water splitting at photosystem II, no NADPH is formed and no oxygen is released. This mechanism mainly serves to supply ATP to balance the energy needs of the chloroplast, especially when more ATP is required than NADPH for the Calvin cycle.

More practice questions