Meiosis and Mitosis

• a process which produces sex cells (gametes), such as sperm and egg cells, for reporudction. • Starts off with a parent cell (diploid cell) which eventually splits into 4 non-identical daughter cells (4 haploid cells)

a gamete is a reproductive cell of an animal or plant They are produced through a process called Meiosis. They contain only one set of chromosomes (23 for humans) and are therefore referred to as a haploid cell.

Contain only half of the genetic information required to produce an individual.

Full set of genetic information (46 chromosomes)

single copy chromosome

two sister chromatids make up a chromosome.

IPMAT Interphase Prophase Metaphase Anaphase Telophase

A diploid cell replicates it’s DNA to form sister chromatid chromosomes.

Homologous chromosomes pair up allowing crossing over. Spindle Fibres Form

Homologous chromosomes pair up in random assortment at the cell equator Spindle Fibres attatch

The cell begins to divide, separating Homologous chromosome pairs Spindle fibres pull them apart

The cell fully divides, forming two haploid daughter cells with sister chromatid chromosomes.

Pairs of chromosomes which carry the same genes

where homologous chromosomes pair up so closely together that they physically swap sections

Homologous chromosomes line up in random orientation

Random assortment and Crossing over are key to producing unique individuals

PMAT Prophase II Metaphase II Anaphase II Telophase II Follows the same process as Meiosis I EXCEPT

each cell starts with only one chromosome from each homologous pair, therefore it is initially a haploid (half genetic information).

Chromosomes line up at the equator Spindle fibres attach to chromosomes.

sister chromatids are separated (instead of homologous pairs)

Each cell fully divides into another two cells.

The end result is four non-identical haploid daughter cells with single chromatid chromosomes.

• A diploid (2n) parent cell copies each of it’s single chromatid chromosomes to become sister chromatid chromosomes • The chromosomes are split equally into two haploid (n) daughter cells. • There are two stages of Meiosis, each following the steps of reproduction

• Produces cells to repair damaged tissues and replace old or dead cells. • For growth and repair. • Starts of with 1 diploid cell (parent cell). • Outcome is two genetically identical daughter cells (diploid)