Back to your test review

In a chloroplast exposed to light of 690 nm only, which product will be formed?

  • (a) ATP only Correct
  • (b) NADPH and O2 Your answer
  • (c) no product Your answer
  • (d) ATP, NADPH and O2 Your answer
Your answer: Correct answer: (a)
Advertisement

Explanation

Why (a) is correct

Light of 690 nm (beyond 680 nm) excites PS I but hardly PS II. So only cyclic photophosphorylation runs, and only ATP is formed.

Why the other options are wrong

  • (b) · your answer NADPH and O2 need PS II working, which 690 nm light cannot drive well.
  • (c) · your answer PS I still works, so ATP is formed.
  • (d) · your answer Without PS II there is no NADPH or O2.
NCERT point: Cyclic photophosphorylation occurs when only light of wavelength beyond 680 nm is available.
What is wrong?
Thank you! We will check this question.
Practise Photosynthesis in Higher Plants
Take a free 15-question NEET Biology test on this chapter. Timed, scored instantly.
Start free test

Similar questions

If two molecules of water are split in the light reaction, the maximum number of NADPH molecules that can be formed is Read the statements and choose the correct option.Statement I: In non-cyclic photophosphorylation, electrons are not ret… Assertion (A): The thylakoid lumen becomes acidic during the light reaction.Reason (R): Protons from water splitting and…