Difference between Respiration and Combustion (Burning)

Respiration is the most important process of gaseous exchange, where O2 is taken in and CO2 is liberated outside in all the living beings.

Hackett (1959) called respiration ‘life with air’. According to him, respiration is a complex process which includes following processes.

a) Oxidation and fragmentation of organic compounds

b) Transfer of electrons which ultimately form water by the union of hydrogen and oxygen.

c) Liberation of energy which is utilized in various physiological process

Combustion or Burning : It is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can produce light in the form of either glowing or a flame.

Lavoisier demonstrated that respiration is a combustion process in which the energy is produced in the same way as is produced by burring the coal but both the processes differ in the following way.

Respiration vs Combustion (Burning)

Respiration

1. It is a biological process. It is under biological control.

2. It takes place at normal temperature.

3. Respiration is a slow process. Thus the energy is also liberated in several steps and remain stored in the form of ATP.

4. Several enzymes are involved. The process is bio chemical.

5. Only part of energy is liberated as heat.

6. Oxygen is employed as an oxidant only at the end of the reaction. 

Combustion or burning

1. It is a chemical process. It is an uncontrolled process.

2. It takes place at high temperature

3. Combustion is a fast process in which the energy is liberated only in one step resulting in increase in temperature and production of fire.

4. Enzymes are not involved. The process is physio chemical.

5. Most of the energy is produced as heat.

6. Oxygen is directly used in the process.