Cells

 

The Cell is the basic structural, functional, and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently, and are often called the "building blocks of life". The study of cells is called cell biology.

 

The cells can be broadly classified into two categories as follows :-

 

1. Prokaryotic Cells - the cells which do not contain a nucleus and are usually single-celled organisms

2. Eukaryotic Cells  - the cells which contain a nucleus and can be either single-celled or part of multicellular organisms.

 

Prokaryotic cells were the first form of life on Earth. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus. Prokaryotes include two of the domains of life, bacteria and archaea. Most prokaryotes range from 0.5 to 2.0 µm in diameter.

 

Eukaryotic Cells include plants, animals, fungi, slime moulds, protozoa, and algae. These cells are about fifteen times wider than a typical prokaryote and can be as much as a thousand times greater in volume. The main distinguishing feature of eukaryotes as compared to prokaryotes is compartmentalization i.e. the presence of membrane-bound organelles in which specific metabolic activities take place. Most important among these is a cell nucleus which houses the eukaryotic cell's DNA. This nucleus gives the eukaryote its name, which means "true nucleus". 

 

To know more about various other aspects of cells, please refer to the menu or the links below: