Question

Explain the cell theory.

Answer 1

The Cell theory was proposed by M.J. Schleiden and Theodore Schwann. It states that the bodies of all organisms are made up of cells and their products so that cells are units of both structure and function of living organisms.

Modern cell theory has the following postulates:

1. All organisms are composed of cells and their products.
2. Cell consists of nucleus, cytoplasm, cell organelles.
3. All cells arise from pre-existing cells i.e. no cell originates spontaneously but comes into being only by division of cells.
4. Every organism starts its life as a cell.
5. All cells show similarity in structure, chemical composition and function.
6. Genetic information is stored and expressed inside cells.
7. Cells contain hereditary material.
8. Cells are responsible for carrying out metabolic activities within living organisms.
9. The function of an organisms is the result of the coordinated activities and interaction of the cell constituents.
10. Cell is the structural and functional unit of life. All vital functions of an organism occur within cells.