Meiosis and Mitosis

The process of meiosis and mitosis are both important to living organisms because they are both part of the cell cycle that prepares the cells for reproduction to make new cells and in the process of making an entire organism.

The process of mitosis is a form of cellular reproduction where a single cell, known as the parent cell, divides and produces two new cells, called the daughter cells. The new cells are genetically identical to each other and to the parent cell. Mitosis does not require genetic information from two different parents. This makes the process asexual. Mitosis needs to occur when a cell grows, when a cell becomes damaged, or when worn cells are replaced and for reproduction of cells.

Mitosis occurs in single celled organisms, hydra, and bacteria.

The process of meiosis is also a step in the cellular reproduction of the cell cycle. This is a prelude to sexual reproduction in humans and other animals. The cells that are to be gametes, or sex cells, divide by meiosis. They have to go through this process twice so that they end up with half the number of chromosomes as the original cell. Meiosis reduces the number of chromosomes in each daughter cell to one-half, so that the number always stays constant from one generation to the next. Without the reduction of the chromosomes during meiosis, the chromosomes would double during reproduction instead of decreasing to exactly one-half. The chromosomes that each daughter cell gets are a mix of both parent cells, instead of just one as in the case of mitosis. If they were to continue to produce and not decrease, the chromosomes would double with each generation until they would be too large to exist.

Meiosis occurs in plants, animals, and insects.