Question

Name the two ways in which glucose is oxidized to provide energy in various organisms.

Answer 1

Hint: In general, the breakdown of glucose molecules requires two steps. During the first step, it splits into three carbon molecules termed pyruvate. The pyruvate is further broken into energy in various forms in different species.

Complete step by step answer: Glucose is a critical source of energy for all life. The food eaten is transformed into carbohydrates, of which glucose is the main ingredient. Glucose is oxidised to provide the body with energy.
The following are the various ways in which glucose is broken down:
-Anaerobic Respiration
-Aerobic Respiration
-Lack of Oxygen
-Anaerobic Respiration: In the absence of oxygen, the anaerobic respiration process takes place. For example, in yeast during fermentation. During this process, pyruvate is converted to ethanol and carbon dioxide. As there is no oxygen present, the bacteria break down food and release just 2mol of ATP together with carbon dioxide and ethanol. The amount of energy released is very less in this process.
-Aerobic Respiration: In aerobic respiration, pyruvate breakdown occurs in the presence of oxygen to give rise to 3 molecules of carbon dioxide and water. The transfer of energy from aerobic respiration is much greater than anaerobic respiration. Oxygen inhaled dissolves food glucose into 36 ATP molecules by glycolysis, citric acid cycle, and electron transport mechanism. As a result, glucose is oxidised to release energy , i.e. 36ATP mol.
-Lack of Oxygen: At moments when there has been a lack of oxygen in our body , particularly during vigorous exercise, in our muscles, pyruvate is converted into lactic acid, which is a 3-carbon molecule compound. The production of lactic acid in muscles induces cramping.

Note: Energy metabolism includes numerous biochemical ways of converting energy and controlling thousands of chemical reactions. Without fine regulation of these metabolic processes, cells and organisms can not sustain life-related activities.