Question

A cell might perform anaerobic respiration for which of the following reasons? a) It lacks glucose for degradation. b) It lacks the transition reaction to convert pyruvate to acetyl-CoA. c) It lacks Krebs cycle enzymes for processing acetyl-CoA to CO2. d) It lacks a cytochrome oxidase for passing electrons to oxygen.

Answer 1

It lacks a cytochrome oxidase for passing electrons to oxygen.

Step-by-step explanation:

During aerobic respiration, the NADH and FADH2 formed during glycolysis and Kreb's cycle are oxidized through the electron transport chain. NADH and FADH2 pass their electrons to the molecular oxygen via four complexes electron transport chain. Cytochrome oxidase is also called a complex IV of the electron transport chain. It serves to carry the electrons from cytochrome c to molecular oxygen, reducing it to H2O.

In the absence of cytochrome oxidase, electrons from NADH and FADH2 will not be passed to the molecular oxygen. Oxidation of NADH and FADH2 is required to continue glycolysis and Kreb's cycle. Therefore, in the absence of cytochrome oxidase, the cells will perform anaerobic respiration to oxidize NADH into NAD+ so that glycolysis can be continued as a source of energy.