Question

Non-cyclic photophosphorylation differs from cyclic photophosphorylation in that the latter has

• A. Only PS I
• B. Evolution of oxygen
• C. Reduction of NADP${}^{+}$
• D. Both B and C

Answer 1

The correct option is A Only PS I

The Light reaction involves the participation of a large number of pigment molecules which are distributed in two separate complexes- PS I and PS II.

In this reaction the excited electron move through two pathways- non-cyclic and cyclic. Non-cyclic electron transport involves the participation of both PS II and PS I whereas cyclic electron transport involves only PS I.

Cyclic electron transport occurs when the electrons released from PS I are returned back to PS I through electron transport pathway without reducing NADP${}^{+}$ $. This pathway serves to generate extra ATP.

Hence, the correct answer is 'Only PS I'.