Aerobic respiration is the process of cellular respiration that takes place in the presence of oxygen gas to produce energy from food. It is a catabolic and exergonic process that takes place inside the cells. The complete process of aerobic respiration occurs in four different stages:

1. Glycolysis: It is the primary step of aerobic respiration and takes place within the cytosol of the cell. During the glycolysis process, the glucose molecules are splitting and separated into two ATP and two NADH molecules, which are later used in the process of aerobic respiration.

2. Formation of Acetyl Coenzyme A: After glycolysis, the pyruvate molecules are transported into the mitochondria, where they are converted into acetyl CoA. This process is called the link reaction.

3. Citric Acid Cycle: The third step in aerobic respiration is the citric acid cycle, which is also called the Krebs cycle. In this stage of aerobic respiration, the acetyl CoA combines with oxaloacetate and produces citric acid. The citric acid cycle undergoes a series of reactions and produces 2 molecules of carbon dioxide, 1 molecule of ATP, and reduced coenzymes such as NADH and FADH2.

4. Electron Transport Chain and Chemiosmosis: The final stage of aerobic respiration is the electron transport chain and chemiosmosis. In this stage, the reduced coenzymes NADH and FADH2 are oxidized, and the energy released is used to generate ATP. The electron transport chain and chemiosmosis take place in the inner mitochondrial membrane.

Aerobic respiration occurs in the mitochondrial matrix of the cell in all multicellular organisms, including animals, plants, and other living organisms.