Q4. Under what light condition does cyclic photophosphorylation also occur, according to NCERT?
When only light of wavelengths beyond 680 nm is available for excitation (NCERT page 140).
Q5. Assertion: the pH of the thylakoid lumen falls in the light. Reason: protons accumulate in the lumen and decrease in the stroma. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (NCERT page 141).
Q6. What four things does chemiosmosis require?
A membrane, a proton pump, a proton gradient and ATP synthase (NCERT page 142).