Indicate whether each of the following descriptions better applies to cytochrome c oxidase complex (O), cytochrome c reductase complex (R), or NADH dehydrogenase complex (N). Your answer would be a four-letter string composed of letters O, R, and N only, e.g. RONN.
( ) It is the largest of the three respiratory complexes.
( ) It accounts for the majority of O? uptake in most cells.
( ) It employs the Q cycle to increase proton pumping.
( ) It contains separate modules for electron transport and proton pumping.

Question

Indicate whether each of the following descriptions better applies to cytochrome c oxidase complex (O), cytochrome c reductase complex (R), or NADH dehydrogenase complex (N). Your answer would be a four-letter string composed of letters O, R, and N only, e.g. RONN.
( )	It is the largest of the three respiratory complexes.
( )	It accounts for the majority of O? uptake in most cells.
( )	It employs the Q cycle to increase proton pumping.
( )	It contains separate modules for electron transport and proton pumping.

Quizplus · Accepted Answer

NADH dehydrogenase complex is the largest respiratory enzyme complex embedded in the inner mitochondrial membrane and contains separate modules for electron transport (from NADH to ubiquinone) and proton pumping (across the membrane out of the matrix). The cytochrome c reductase complex reduces cytochrome c using electrons delivered by ubiquinol by the Q cycle mechanism. Finally, the cytochrome c oxidase complex accepts electrons from cytochrome c and reduces O?.

Indicate Whether Each of the Following Descriptions Better Applies to Cytochrome