Illustrate in detail about the Cell
The present day study of cells combines many scientific disciplines, like biochemistry, biophysics, genetics, microscopy and physiology. A great deal has been understood about cells, especially in the last 35 years, regarding how they are constructed, how they function, and how they work together in complex organisms. Still, much remains to be learned. The term 'cell' was first used by Robert Hooke in 1664 to denote the little box-like structures, which he observed in cork tissue under a primitive microscope. A contemporary of Hooke, Antonie van Leeuwenhoek, discovered sperm cells, red blood cells and a variety of microorganisms, again using a microscope consisting of a single lens. However, these initial observations led to nearly two centuries of microscopic study of cells, and, with the gradual introduction of more and more powerful microscopes, the cell nucleus was also discovered. Thus, the cellular nature of all plants and animals came to be recognised. By 1830's, it was proposed that all organisms are constructed of-cells. This statement is now known as the cell doctrine or cell theory.