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) Respiration is a stepwise oxidation of organic molecules in a cell involving main three steps.
(ii) Krebs' cycle
(iii) Electron transport chain
Glucose passes through series of emphatically controlled reactions and is finally converted into H2O+ATP+CO2.
(ii) Organic substances are the molecules normally found in living systerns. They are X usually composed of carbon atoms in rings or long chains to which other atoms such as hydrogen, oxygen and nitrogen are attached. e.g., glucose, fatty acids, amino acids etc. These molecules bumt as substrate to produce energy. Respiration of glucose a. fatty acids is called f,aling respiration a. respiration of protein and amino acids are called protoplasm, respiration.