Aerobic and anaerobic respiration

• Respiration occurs in the presence of oxygen as well as in the absence of oxygen. So, respiration is primarily of two types:

    (i)  Aerobic respiration

    (ii) Anaerobic respiration

Aerobic Respiration:

• The process of respiration that takes place in the presence of oxygen is called aerobic respiration.
• This results in the release of energy, and in the formation of carbon dioxide and water.
• Aerobic respiration is represented by the equation:

Sugar  + Oxygen → Energy + Carbon dioxide + Water

• Aerobic respiration is the most efficient form of respiration.
• The reaction involved in this process is similar to that of combustion or burning.

Anaerobic Respiration:

• The process of respiration that takes place in the absence of oxygen is called anaerobic ("an" means "without") respiration.
• This results in the release of energy, and in the formation of carbon dioxide and ethyl alcohol (an organic compound). It is represented by:

Sugar → Energy + Carbon dioxide + Ethyl alcohol

• Our muscle cells can also respire anaerobically but only for a short time, when there is a temporary deficiency of oxygen.
• During heavy exercise, fast running, cycling, walking for many hours or heavy weight-lifting, the demand for energy is high.
• But the supply of oxygen to produce the energy is limited.
• Then anaerobic respiration takes place in the muscle cells to fulfill the demand of energy.