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Cell: Definition, Types, Functions and Division (Part 2)

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History and Origin    A cell was defined as “ unit of biological activity delimited by a semi permeable membrane and capable of self-reproduction in a medium free of other living systems” by Loewy and Siekevitz (1963) . The study of cell has been made possible with the help of light microscope. Robert Hooke (1665) with the help of light microscope discovered that a section of cork is made up of small cavities surrounded by firm walls. He used the term “cell” for the first time to describe his investigations on the “texture of a piece of cork”. Later on A. Van Leeuwenhoek (1632-1723) observed various unicellular organisms and cells like bacteria, protozoan’s, red blood cells and sperm etc.    He observed nucleus in some erythrocytes and all this was made possible with the improved microscopes. In 1809, Mirble M. stated that all plant tissues are composed of cells. In the same year, importance of cells in living organisms was described by J.B. L...
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Cell: Definition, Types, Functions and Division (Part 1)

Ce ll , in biology , is the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed of. Cells are the smallest structural units of living matter and make up of all living things.  A single cell is often a complete organism in itself, such as a bacterium o r yeast.  Other cells acquire  specialized functions as they mature. These cells cooperate with other specialized cells and become the building blocks (Tissue) of large multicellular organisms, such as humans and other animals . Although cells are much larger than atoms,  they are still very small. In 1655, Robert Hook, an English Scientist was inspecting a dried portion of the cork tree with a crude light microscope. during this examination, he came across several microscopic compartments that he termed "cells." This was such a significant discovery that it forever altered basic biology theory and research.  The smallest known cells are a group of t...
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