Question

Which statement describes the functioning of photosystem II?

A. The splitting of water yields molecular carbon dioxide as a by-product.

B. Light energy excites electrons in the electron transport chain in a photosynthetic unit.

C. The electron vacancies in P680 are filled by electrons derived from water.

D. The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+.

E. The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit.

Tell me the answer, and explain why that choice is the answer and why other choices are not answers!! (This is important part, I have to understand why other choices are not answers)

Answer 1

Answer:

A. The splitting of water yields molecular carbon dioxide as a by-product.------------------------- As photosystem II involves in photosynthesis, CO2 is not by product--------------WRONG

B. Light energy excites electrons in the electron transport chain in a photosynthetic unit.---------------- It occurs both in Photosystem I & II -----------WRONG

C. The electron vacancies in P680 are filled by electrons derived from water. -------------------The electrons are excited by light energy and the electron vacancy in P680 is filled by photolysis of water-------CORRECT

D. The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+.---------- Protons are donated 700 by Pto NADP+ not to NADPH ----------WRONG

E. The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit. ----------------P700 is not reaction center in photosystem II --------WRONG