Respiration is an energy releasing and enzymatically controlled catabolic process which involves a step-wise oxidative breakdown of organic substances inside living cells.
In this statement about respiration explain the meaning of
(i) Step-wise oxidative breakdown
(ii)Organic substances (used as substrates)
(i) Step-wise oxidative breakdown
The oxidation of an element does not happen in one single go. It happens in a step by step process known as a step-wise oxidative breakdown. The cells of our body also require some energy to perform other functions. This step by step release of energy would ensure proper utilisation of energy and make it large enough to be associated with the synthesis of ATP molecules.
ii) Organic Substances
Organic substances are the ones which are present in the living organisms. These substances are oxidised in the process of respiration so as to release energy. Examples of organic substances are carbohydrates, proteins and fats.