Which of the following is true regarding the given electron transport chain `CoQ -> Cytc -> Ayt aa_3 -> O_3`

Options

A. `CoQ rarr Cyt` c is `H^(+)` absorbing site
B. `aa_(3)rarrO_(2), H^(+)` yielding site
C. `CoQ rarr Cyt` c is `H^(+)` yielding state and `aa_(3) rarr O_(2)` is `H^(+)` absorbing site
D. no `H^(+)` is absorbed or released

Answer

C

Explanation

In electron transport chain electrons transport through a series of carriers. `H^(+)" of "NADH^(+)` (received from Krebs cycle) is accepted by FAD as a result of which FAD is reduced to `FADH^(+) and NADH^(+)` is oxidised to NAD. Reduced `FADH^(+)` is oxidised by CoQ, with the formation of `CoQH^(+). H^(+)` ions then move to Cyt b, then Cyt c, Cyt a and Cyt `aa_(3)`. Ultimately these `H^(+)` are acceped by `O_(2)` and `H_(2)O` is formed.