What are different ways in which glucose is oxidised to provide energy in various organisms?

Explanation

(1)Glucose is the most commonly used sugar for deriving energy in plants, animals and in micro-organisms.
(2)In all these organisms glucose is oxidised in two stages.
(3)The first stage is known as Glycolysis. It occurs in cytoplasm.
(4) During glycolysis glucose is converted to two molecules of pyruvic acid.
(5)In the second stage, if oxygen is available pyruvic acid is converted to `CO_2` and water, large amount of energy is released. This is known as aerobic respiration. In most of the plant and animal cells aerobic respiration occurs.
(6)If oxygen is inadequate or not available, pyruvic acid is converted into ethanol and carbon dioxide. This is anaerobic respiration, taking place in yeast cells that is called fermentation.
(7)If oxygen is not available in muscle cells, the pyruvic acid is converted into lactic acid.