Question

Growth is one of the characteristic of all living organisms? Do unicellular organisms also grow? If so, what are the parameters?

Answer 1

Growth:

Growth is the most fundamental characteristic of living beings. It is characterised by an irreversible, permanent increase in the size of

• an individual cell
• an organ or its parts
• an organism

over a period of time.

Growth in unicellular organisms:

Unicellular organisms divide to produce daughter cells. In them, growth is synonymous with reproduction.

This is followed by the growth of daughter cells which is accomplished by accumulation of protoplasm.

Parameters in unicellular organisms:

Following are the parameters of growth in unicellular organisms:-

• Increase in the number of cells: This can be easily observed by counting the number of cells in a cell culture under the microscope.
• Increase in mass: Though not very significant as in multicellular organisms, it occurs in unicellular organisms also so as to transform daughter cells into matured ones.