What occurs during oxidative phosphorylation?

A. ATP production using electrons from NADP
B. Coupling of ATP synthesis to electron transport
C. Chemiosmosis in the matrix of the mitochondrion
D. Release of energy as ATP reacts with oxygen

B

This was the hardest question on the paper, with only 28% of candidates answering correctly. If all candidates had guessed the answer we would expect 25% to be correct, but we should not assume that only 3% of candidates got the answer here by deduction rather than guesswork. The discrimination index shows that most candidates were not guessing. The commonest answer chosen by candidates was A, and was incorrect; ATP is not produced using electrons from NADP during oxidative phosphorylation. This may be another case of candidates not reading the question carefully enough, with the letter P making all the difference.