Meiosis: How our bodies make egg and sperm cells

1. Parents can produce many types of offspring Families will have resemblances, but no two are exactly alike.

2 Every body cell has a nucleus Every nucleus has chromosomes The number of chromosomes depends on the species

3 Genes are located on Chromosomes Genes control the traits of the individual such as looks( Phenotype) and behavior and genes (Genotype)

4. Chromosomes come in matching pairs These are called Homologous Chromosomes. Does this normal Karyotype from a boy or a girl?

4 Cells in your body have a complete set (46 chromosomes) They are called Diploid. Sex Cells (Egg and Sperm) only have half (23 Chromosomes) They are called haploid.

Diploid vs. Haploid Human Cell

Diploid vs Haploid Cells

Find the Hololog..!!

When GAMETES combine, the Zygote (new offspring) gets half from Mom (23 chromosomes) and half from Dad (23 chromosomes) Zygotes are diploid (46 chromosomes)

Video Clip: Swim of the Sperm When sperm and egg meet, their chromosomes must match up for Zygote to develop properly.

Lets Review Vocabulary …. 1. Matching sets of chromosomes are called ___________________________________ pairs. 2. Egg and sperm combine to make a ____________________________. 3. Egg and sperm are both known as ___________________________________. 4. A cell that only has half of a set of chromosomes is said to be ____________________________________. 5. A cell that has a complete set of chromosomes is said to be ______________________________________. 6. Genes are located on ______________________________.

The process of creating a gamete (sex cell) is called MEIOSIS It is similar to Mitosis, but will produce 4 different daughter cells that are each haploid. Oogenesis – makes egg cells in the Ovaries. Spermatogenesis – makes Sperm cells in the Testes.

Stages of Mitosis

Special Stages of Meiosis Prophase 1 of Meiosis Homologous Chromosome pairs match up. Chromosomes exchange pieces of DNA (genes). This is called Crossing Over – causes variety in a family‘s gene pool & Allows siblings to look unique and different from each other.

Self Test – Exit Ticket The purpose of MEIOSIS is to: a) create identical daughter cells b) create 4 unique cells for reproduction c) create 4 new organelles to build new cells d) copy DNA so that cells can repair themselves MEIOSIS only occurs in what type of cells a) Zygote c) Gametes b) Skin Cells d) Mitochondria