Question

Pigment system- I conducts

• A. Cyclic photophosphorylation
• B. Non-cyclic photophosphorylation
• C. Both (A) and (B)
• D. None of the above

Answer 1

The correct option is C Both (A) and (B)

Z scheme of light reaction is non cyclic fow of electron from PSII through quinone, cyt b6b6 f complex and plastocyanin to NADPH via PSI; it does not return to PSII. NADP reductase enzyme is located on stromal side of PSI; Z scheme includes both PSI and PSII. Absence of PS-II leads to cyclic photophosphorylation in which electrons are passed from PS-I, via electron transfer chain, to back to PS-I with formation of ATP. Cyclic photophosphorylation does not pass electrons to NADP; rather electrons are passed back to PSI. PS I is involved in both cyclic and non cyclic photophosphorylation. Correct answer is B.