Cyclic vs Non-Cyclic Phosphorylation (Set 3/6)

What is photophosphorylation?

The process of making ATP using light energy.

What is cyclic photophosphorylation?

A pathway using Photosystem I only that produces ATP.

What is non-cyclic photophosphorylation?

A pathway using Photosystems I and II that produces ATP, NADPH, and oxygen.

Which photosystem is used in cyclic photophosphorylation?

Photosystem I only.

Which photosystems are used in non-cyclic photophosphorylation?

Photosystem I and Photosystem II.

What does cyclic photophosphorylation produce?

ATP only.

What does non-cyclic photophosphorylation produce?

ATP, NADPH, and oxygen.

Do electrons return to the photosystem in cyclic photophosphorylation?

Yes. They cycle back through the electron transport pathway.

Do electrons return to their original photosystem in non-cyclic photophosphorylation?

No. They eventually help reduce NADP+ to NADPH.

Which pathway splits water and releases oxygen?

Non-cyclic photophosphorylation.

What is the easiest way to remember cyclic vs. non-cyclic?

Cyclic = ATP only. Non-cyclic = ATP + NADPH + O2.