How come everyone looks different, but sometimes family members look similar?

Gene Transfer Asexual Reproduction Meiosis Sexual Reproduction Sex Cells

Two Kinds of Reproduction Asexual 1 parent cell Mitosis occurs (copying) Includes single celled organisms and some of the cells in your body. Ex. Rotifers Sexual 2 parent cells join together Includes humans, some animals, and pea plants. Ex. Deer

Gamete Cells Known as gametes Are the parent cells There are female and male cells Each gamete has one of the chromosomes from each homologous pair. Ex. Each carry 23 chromosomes.

Why is it important that gamete cells have half the usual number of chromosomes? When the cells join, the total number of homologous chromosomes can only be 46!

How does this relate to genes? Genes are located on chromosomes!

Meiosis Produces new cells with half the usual number of chromosomes or 23. (Mitosis has 46) Gametes are made during meiosis. 8 steps. Meiosis- Mitosis-

This is animated!

Meiosis 1 Each chromosome makes an identical copy or 2 halves of chromatids. Chromosomes thicken/shorten Nuclear membrane disappears

Meiosis 2 Homologous chromosomes line up at the equator of the cell.

Meiosis 3 Chromosomes separate from homologous partner Move to opposite ends of the cell

Meiosis 4 Nuclear membrane re-forms Cell divides Chromatids are still joined.

Meiosis 5 The 2 cells have a member of each homologous chromosome pair

Meiosis 6 The chromosomes line up at the equator of each new cell.

Meiosis 7 Chromatids pull apart Move to opposite ends Nuclear membranes form

Meiosis 8 4 new cells have formed. Each cell has ½ the original cell’s chromosomes.

This is a cool site for practicing mitosis and meiosis!

Complete the following Venn Diagram MitosisMieosis