The cell is the structural and functional unit of all living things. It is the part of the living being (or even the living being if it is unicellular) that performs the three vital functions of living beings: nutrition, relationship and reproduction.
Although there are unicellular living beings, most are multicellular. Because the cells are very small, they could not be observed or studied until the techniques of observation allowed it with inventions such as the microscope.
- The plasma membrane is a layer of lipids and proteins that surrounds the cell. It is responsible for regulating the passage of substances between the outside and the inside of the cell.
- The cytoplasm is the part of the cell that is surrounded by the membrane. It is formed by an aqueous medium (cytosol) in which the cellular organelles float. Organelles are structures responsible for carrying out various functions.
- The genetic material (DNA) is substance containing the hereditary information and controls the operation of the cell.