Cell Division Cell Division Each cell in the

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