Question

How does the process of respiration occur in living organisms?

Answer 1

Hint: respiration occurs in both plants and animals. It is a biochemical reaction that occurs in all living cells. It results in production of energy in the form of ATP and NADPH.

Complete answer: respiration is a metabolic process in which an organism oxidises nutrients to produce energy and releases the waste products. Respiration occurs at 2 levels, cellular and physiological. Cellular respiration takes place in the cells of the organism, whereas physiologic respiration deals with the diffusion and transport of metabolites between the external environment and the organism. In cellular respiration, glucose and oxygen are the reactants (for aerobic respiration) and carbon dioxide, water, and ATP are the products. The process of respiration is different for plants and animals.
Respiration in plants- Sugars produced from photosynthesis is broken down in presence of oxygen to produce ATP. Oxygen enters the plants through stomata. Leaves, stems and roots of the plant, all are sites of respiration. The process of respiration is represented as follows:

$$C_6{H}_{12}{O}_6+6O_2\to 6C{O}_2+6H_{2}O+32ATP$$

The site of respiration inside cells is the mitochondria .Respiration in plants occurs in the presence of oxygen, and therefore is called "aerobic respiration".

Respiration in animals- animals take up oxygen by nostrils or through gills, some animals use their skin for the same. Mammals take up oxygen by the mechanism of breathing. The oxygen is then carried to each cell by means of haemoglobin where respiration occurs.

Note: Though the process of respiration varies among organisms, the sole purpose of it remains constant which is production of energy.