Question

after glycolysis, the pyruvate molecules can follow two different metabolic routes: aerobic and anaerobic respiration. what is the main difference between these?
a) they are the same metabolic pathway, occurring in different locations
b) anaerobic respiration does not need oxygen to occur and aerobic respiration does
c) anaerobic respiration does not occur in mammalian cells
d) aerobic respiration occurs in the presence of oxygen and anaerobic respiration is inhibited in its presence

Explanation:

• Option a is incorrect: they are distinct metabolic pathways, not the same.
• Option c is incorrect: anaerobic respiration (like lactic acid fermentation) occurs in mammalian muscle cells during oxygen deprivation.
• Option d is incorrect: while aerobic respiration needs oxygen, anaerobic respiration is not just inhibited by oxygen; its core defining feature is that it does not require oxygen at all.
• Option b correctly states the primary difference: aerobic respiration depends on oxygen as a final electron acceptor, while anaerobic respiration uses alternative electron acceptors and does not require oxygen.

Answer:

b) Anaerobic respiration does not need oxygen to occur and aerobic respiration does