Cell Division

Cell Division Each cell in the body must carry a complete set of chromosomes. For this reason DNA must be able to replicate and the cell must be able to divide. There are 2 ways by which cells are reproduced: Mitosis Meiosis

Mitosis This is the process by which the body cells divide to form new cells for growth and repair. Every new cell gets a complete set of chromosomes. The cells produced (daughter cells) are genetically identical to the parent cell, i.e. they are exact copies.

Mitosis When the cell is not dividing, the chromosomes are long, thin strands of chromatin. They are invisible. Just before cell division, they shorten and thicken and become visible under the light microscope. Each chromosome has been replicated to form 2 identical strands, called chromatids, which are held together by a centromere.

Mitosis The nuclear membrane disappears. The replicated chromosomes line up at the center of the cell. Spindle fibres attach to each centromere. The spindle fibres contract, the chromatids separate at the centromere and are drawn to each end of the cell.

Mitosis Nuclear membranes forms around each set of chromosomes. The cell divides between each nucleus, resulting in 2 daughter cells which are genetically identical.

Mitosis animation