Respiration – The energy required by our body to stay active is provided by the food which we eat. During digestion, food particles are broken down into simpler substances. For example, wheat, rice, potatoes etc all contain carbohydrates. These carbohydrates are broken down into simpler substances called glucose. The glucose on combustion with oxygen gives CO2 gas, H2O and evolves heat. This reaction is called Respiration.
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
Respiration is a very special form of burning fuel. It involves the burning of sugar with oxygen within the cells of every living organism, to produce the energy needed for all the reactions of life along with water and carbon dioxide as waste products. Respiration is another exothermic reaction.