Explain the three pathways of breakdown in living organisms.

Explanation

In the process of respiration , the first step is the breaksdown of glucose, a 6 - carbon molecule breaks into 2 molecule of 3 -carbon molecule pyruvate . This process takes place in the cytoplasm.
The subsequent breakdown pathway depends on the absence or presence of oxygen as follows
(i) Aerobic respiration It takes place in the mitochondria in the presence of oxygen. Pyruvic acid is converted into carbon dioxide , and water. Thus releasing a lot of energy.
(ii) Anaerobic respiration It takes place in the and ethanol (in case of microbes, i.e., fermentation in yeast) or into lactic acid (in the case of muscles cells during sudden activity in humans.)