Question

Identify the correct sequence of \(e^-\) flow leading to ATP synthesis in cyclic-photophosphorylation:

• A. P 700 \(\rightarrow\) PC \(\rightarrow\) Cyt \(b_6f\) complex \(\rightarrow\) \(A_0/A_1\) \(\rightarrow\) FeS \(\rightarrow\) Fd \(\rightarrow\) P700
• B. P 700 \(\rightarrow\) Cyt \(b_6f\) complex \(\rightarrow\) \(A_0/A_1\) \(\rightarrow\) FeS \(\rightarrow\) Fd \(\rightarrow\) PC \(\rightarrow\) P700
• C. P 700 \(\rightarrow\) Fd \(\rightarrow\) Cyt \(b_6f\) complex \(\rightarrow\) PC \(\rightarrow\) \(A_0/A_1\) \(\rightarrow\) FeS \(\rightarrow\) P700
• D. P 700 \(\rightarrow\) \(A_0/A_1\) \(\rightarrow\) FeS \(\rightarrow\) Fd \(\rightarrow\) Cyt \(b_6f\) complex \(\rightarrow\) PC \(\rightarrow\) P700

Hint:

Cyclic photophosphorylation occurs when the plant needs extra ATP relative to NADPH, or when \(CO_2\) levels are low, as it bypasses the reduction of \(NADP^+\).

Answer 1

The Correct Option is D