Cell Cycle and Cell Division

A cell is a unit of life. A cell undergoes all the life processes like, birth, growth, reproduction etc. The life cycle of a cell is termed as cell cycle. The growth and development and reproduction of an organism depends upon cell division. Three types of cell division are seen in animals and plants. These are: amitosis, mitosis and Meiosis.

Amitosis or binary fission:

In amitosis or direct cell division, the nucleus get elongated first. Then it assumes a dumb bell shape and a constriction divides the nucleus into two nuclei. Then constriction of cytoplasm continues and gives rise to two new cells.

Mitosis:

In mitosis, two daughter cells are formed with chromosome number remaining same as parent cell. The process of mitosis is divided into different phases, viz.,

• Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis

Drugs and Drug Targets:

Integrins are also trans membrane binding glycol proteins that usually bind cells to matrix. However, they also may bind cells to cells. Binding is calcium dependent. Binding is from an integrin to a specific ligand on the target cell Binding may involve actin filaments, but is not associated with a cell junction Integrins contain an alpha and a beta subunit: Most cell to cell interactions involve integrins with an alpha and a beta-2 subunit

Meiosis:

Meiosis takes place in germ cells i.e., the cells of testes and ovaries. In the meiotic process, chromosomes divide once and cytoplasm divides twice. Thus four haploid cells are formed from one diploid zygotic cell. Meiotic division takes place in following phases:

• First Meiotic division- it comprises of few sub phases. In this stage, two haploid cells are formed from one diploid cell.
• Second meiotic division is basically mitotic division, in which previously formed two haploid cells give rise to four haploid cells.

Main differences between Mitosis and meiosis: