1. Meiosis

2. Sexual Reproduction Requires 2 parents
Sex cells have half the chromosomes as body cells
When 2 parent sex cells combine, a body cell is produced and it has a full set of chromosomes
Variety in offspring

3. Homologous Chromosomes
In body cells chromosomes are found in pairs.
The pairs are called homologous chromosomes (same structure and size).
They carry the same genes (can be different versions of the same gene).
Example: One chromosome pair is for sex chromosomes
Females XX
Males XY
Cells with a pair of every chromosome are called diploid.

4. Sex Cells Sex cells are called gametes.
Gametes have half the number of chromosomes.
Gametes are haploid, meaning they have one chromosome from each homologous pair.
Gametes are made in reproductive organs.
Egg- female gamete
Sperm- male gamete

5. Answer the question on p. 273

6. Meiosis The type of cell division that produces haploid sex cells
When an egg is fertilized by a sperm cell, a new diploid cell forms.
Meiosis makes 4 haploid cells
Meiosis has 2 parts

7. Meiosis I
Chromosomes are copied before meiosis I
p. 274

8. Meiosis II The two cells made in meiosis I will divide in meiosis II
The result is 4 haploid cells
In males it’s 4 sperm cell and in females it’s 4 egg cells

9. p. 275

10. Mitosis vs. Meiosis
Use the info on p. 276 to complete the chart.