Question

Which is not true regarding the cyclic electron transfer system (ETS) in photosynthesis?

• A. A possible location of cyclic electron transfer system is in the stroma lamellae
• B. Only PS I is involved
• C. Results only in the synthesis of ATP
• D. External electron donor is required

Answer 1

The correct option is D External electron donor is required

When only PS–I is functional, the phosphorylation occurs due to cyclic flow of electrons. A possible location where this could be happening is in the stroma lamellae. Since there is a cyclic flow of electrons, no external electron donor is required.