Aerobic and Anaerobic Respiration

Aerobic Respiration

Aerobic respiration occurs when oxygen is available. It is the most efficient way to release energy from glucose.
The general equation for aerobic respiration is: Glucose + Oxygen -> Carbon dioxide + Water + Energy
This process takes place in the mitochondria of the cell.
It consists of four stages: glycolysis, link reaction, Krebs cycle, and the electron transport chain.
In glycolysis, glucose is split into two molecules of pyruvate, and some ATP (energy) is produced.
The pyruvate then enters the mitochondrion where the link reaction, Krebs cycle, and electron transport chain occur, releasing more ATP.

Anaerobic Respiration

Anaerobic respiration occurs when there is a lack of oxygen in cells.
Compared to aerobic respiration, it generates less energy.
The overall equation for anaerobic respiration in muscle cells is: Glucose -> Lactic acid + Energy.
The overall equation for anaerobic respiration in yeast (fermentation) is: Glucose -> Ethanol + Carbon dioxide + Energy
Anaerobic respiration occurs in the cytoplasm of the cell.
In animals, this process results in the production of lactic acid. This can lead to muscle fatigue and pain when oxygen is not supplied quickly enough to the muscles during intensive exercise.
In yeast cells, anaerobic respiration results in the production of ethanol and carbon dioxide, a process used in brewing and bread making.

Differences between Aerobic and Anaerobic Respiration

The main difference between the two is the presence or absence of oxygen. Aerobic respiration requires oxygen, while anaerobic respiration does not.
Aerobic respiration releases more energy (ATP) per glucose molecule than anaerobic respiration.
The by-products of respiration are different. In aerobic respiration, carbon dioxide and water are produced. In anaerobic respiration, however, lactic acid (in animals) or ethanol and carbon dioxide (in yeast) are produced.

Students should remember that even though anaerobic respiration is not as efficient as aerobic respiration in terms of ATP production, it is crucial for survival in low-oxygen environments or during strenuous physical activities.