Rotenone is a drug which binds complex i of the electron transport chain and inhibits it from functioning.

(a) can nadh donate electrons to the electron transport chain after rotenone treatment?
(b) can fadh2 donate electrons to the electron transport chain after rotenone treatment?
(c) would you expect oxygen consumption to go up or down with rotenone treatment? why?

a) No; b) Yes; c) Down

Explanation:

a) No: Rotenone inhibits the transfer of electrons from complex I to CoQ of the electron chain by inhibiting the oxidation of NADH to NAD.

b) Yes: Besides receiving electrons from complex I, FADH2 receives electrons  from fatty acids and glycerol-3-phosphate. 2 ATPs are produced from FADH2.

c) Down: Less oxygen will be broken down (or consumed) to water, instead some of it will be converted to reactive oxygen species.

the answer to your question is:

c. complementary base-pairing