Question

Primitive photosynthetic plants utilize solar energy by

• A. Cyclic photophosphorylation
• B. Non-cyclic photophosphorylation
• C. Both A and B
• D. Calvin cycle

Answer 1

The correct option is A Cyclic photophosphorylation

The absence of PS-II in primitive photosynthetic plants leads to cyclic photophosphorylation as noncyclic photophosphorylation involves both PSII and PSI. Cyclic photophosphorylation is non-oxygenic photosynthesis in which electrons are passed from P700 of PS-I, via electron transfer chain, to back to P700 with the formation of ATP. Inorganic compounds, not water, serve as energy/electron source and oxygen is not released. PSI absorbs light below 680nm; low light intensity and anaerobic conditions favor cyclic photophosphorylation. Thus, the correct answer is option A.