CELL
Cell is the minimum unit of life, capable of reproducing itself. Lifetime of a cell is called cell cycle. All cells contain multiple structural units of smaller size. These units are called organelles and perform specific functions, for example, generate energy or cause cells to move. Organelles are surrounded with a liquid cytoplasm, and the whole cell is separated from the outside environment by the cell membrane.
According to their structure, all cells are classified as eukaryotic and prokaryotic, depending on their function - as gametal and somatic.
Human organism consists of over 200 various types of somatic cells. They build various types of tissues. The main types of cells are: epithelial cells, connective tissue cells, nerve cells, muscle cells, sensory cells, blood cells.
Gametal cells (there are two types of them) serve for transfer of hereditary information from parents to their descendants.
The number of cells increases as the result of cell division. Prokaryotic cells undergo binary division, eukaryotic cells - mitosis (or meiosis).