Mitosis

Mitosis is the division of a cell’s nucleus to produce two nuclei with the same genetic information. It is usually followed by division of the rest of the cell, producing two genetically identical daughter cells.

Before mitosis, each chromosome is replicated, producing two identical copies joined together. During mitosis, the copies separate and move to opposite ends of the cell. A nucleus forms around each set, so each daughter cell receives the same genetic information and the same number of chromosomes as the original cell.

What mitosis enables

Mitosis increases cell number for growth. It also produces new cells to repair damaged tissues and replace cells that are lost or worn out.

In asexual reproduction, a single parent produces offspring without the joining of sex cells. Mitosis produces genetically identical cells, so the offspring have the same genetic information as the parent.

The cell cycle

The cell cycle is the sequence in which a cell grows, copies its genetic material and divides. It produces two genetically identical daughter cells. The cycle can be described in three overall stages.

1. Growth and DNA replication

The cell grows and increases the number of sub-cellular structures it contains, including ribosomes and mitochondria. It also copies its DNA in a process called DNA replication. This produces two copies of each chromosome, so that a copy can be passed to each daughter cell.

2. Mitosis

During mitosis, the chromosome copies separate and the nucleus divides. Each new nucleus receives a copy of each chromosome.

3. Cytokinesis

Finally, the cytoplasm and cell membrane divide, separating the cell into two daughter cells. This final division is called cytokinesis. Each daughter cell has the same genetic material as the original cell and as the other daughter cell.