What is Cell Division?
Cell division is a process in which living cells divide into two or more daughter cells. The period between two cell divisions is called a cell cycle. During this period all the cellular contents are correctly replicated. The first thing to be replicated before a cell divides is its genetic material called DNA. Cell division is occurring at every minute in our bodies and is used in growth and repair process because new cells are needed throughout life. Constant cell division also helps maintain the surface area to volume ratio of the cell by not letting the cell grow larger. Depending upon the type of cells the division may be one of the two types: mitosis and meiosis, of which mitosis is a one-step division process whereas mitosis has two divisions called Meiotic I and Meiotic II.
Types of Cell Division
Mitosis refers to the type of cell division in which the parent cell divides into genetically identical daughter cells having the same number of chromosomes. Mitosis results in two diploid (2n) cells and it occurs in all somatic (non-reproductive cells) cells. A diploid cell means the cells which have a paired set of chromosomes e.g. in humans, a cell having 46 chromosomes is a diploid cell.
In Meiosis the daughter cells produced are not genetically identical. Every daughter cell has a unique genetic makeup. Mitosis occurs in all body cells whereas meiosis occurs only in germ cells (sperms and eggs). It is used for sexual reproduction. Meiosis results in four haploid cells (n). A haploid cell means the cell which has half the number of chromosomes than somatic cells e.g. in the case of humans a germ cell having 23 chromosomes is a haploid cell.
Why do cells divide?
Cell division occurs for many reasons. For example, when you accidently cut your finger the process which heals it is cell division. It also occurs for the sake of growth. Every living organism grows. There are almost one trillion cells that divide every day, in a human body. This much division leads to the growth of organisms. So, the most important reasons for cells division are growth and the repair and healing process of organisms.