Question

In which part of the cell does aerobic respiration occur?
A. Mitochondrion
B. Cytoplasm
C. Nucleus
D. Cytoplasm and mitochondrion

Answer 1

Hint: Aerobic respiration is the process which involves the utilization of oxygen in the catabolism of nutrients mainly carbohydrates to carbon dioxide, and water and the electrons produced undergoes an electron transport chain. Here oxygen acts as an electron acceptor. The ATP molecules produced as a result of this process is utilized for energy production.

Complete step by step answer: Mitochondria is the site where aerobic respiration occurs. The phases of aerobic respiration that occurs are glycolysis, Kreb’s cycle and the electron transport chain. It is a membrane-bound organelle present in all cells except red blood cells. It is the matrix of the mitochondria where ETC and Kreb’s cycle occurs.
Considering the other options:
i. Cytoplasm: It is the fluid in which organelles are suspended, many of the biochemical activities of the cells happen at this site. The cytoplasm is the site of occurrence of the anaerobic process also known as glycolysis, which is the first step in cellular respiration. It is the only source of energy in prokaryotes and anaerobes.
ii. Nucleus: The process of respiration does not occur in the nucleus. It contains the genetic material of the organisms. It regulates the process of transcription and cell replication.
Thus, the correct answer is option A.

Note: Glycolysis is the process of energy production in the absence of oxygen. The process produces only two molecules of ATP. It occurs in the cytoplasm. It is a ten-step process. Glycolysis is the major process for respiration in prokaryotes.