Question

A cell might perform anaerobic respiration for which of the following reasons?

a) To produce ATP in the absence of oxygen
b) To reduce CO2 to methane
c) To oxidize organic molecules using an external electron acceptor
d) To fix nitrogen

Answer 1

A cell might perform anaerobic respiration mainly to produce ATP when oxygen is absent. The correct answer is option a).

Step-by-step explanation:

A cell might perform anaerobic respiration primarily to produce ATP in the absence of oxygen. This process allows a cell to convert energy for its use when oxygen is not available, such as in muscle cells during vigorous exercise or in various microorganisms that live in oxygen-depleted environments.

Anaerobic respiration includes both fermentation processes, like alcoholic and lactic acid fermentation, and the use of inorganic molecules as final electron acceptors. For instance, certain prokaryotes, such as methanogens, use carbon dioxide to oxidize NADH, producing methane.

Moreover, denitrifiers can use nitrate to produce nitrogen gas when oxygen is scarce. These anaerobic processes are critical for many organisms to survive and function in environments where oxygen is limited or unavailable.