1. Meiosis

2. Cell Cycle Review Interphase includes G1 S phase G2 Mitosis includes
Prophase
Metaphase
Anaphase
Telophase
The final stage of the cell cycle is Cytokinesis

3. Meiosis – type of cell division that results in 4 daughter cells each with half the number of chromosomes as the parent cell

5. Meiosis IPMATPMAT Meiosis includes Interphase Mitosis I Cytokinisis I
Prophase I
Metaphase I
Anaphase I
Telophase I
Cytokinisis I
Mitosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
A second stage of interphase is missing in meiosis
This is important because the DNA replicates during interphase. Meiosis goes through a second division without replicating the DNA, resulting in cells with only half the DNA as the parent cell

6. Meiosis Meiosis produces 4 haploid cells known as gametes.
Each gamete is UNIQUE and will be used for sexual reproduction.
Diploid number of chromosomes for a human is 46 (2n = 46)
Haploid number of chromosomes for a gamete cell is 23 (n = 23)

7. Sexual Reproduction
Meiosis reduces the chromosome number to one set (n)
Fertilization restores the diploid number (2n) when the gametes are combined
Ex - sperm cell combines with egg cell
In sexual reproduction, two individuals (parents) contribute genes to the offspring. This form of reproduction results in greater genetic variation in the offspring than asexual reproduction.

8. Male vs. Female Meiosis in males produces 4 sperm cells
These sperm cells are haploid cells (n)
Meiosis in females produces 4 egg cells
These egg cells are haploid cells (n)
When the sperm cell combines with the egg cell it results in a diploid zygote (2n)

9. ♂
Male ♂

10. ♀
Female

11. Genetic Variation
Crossing Over: portions of a chromatid on one homologous chromosome are broken and exchanged with corresponding chromatid portions of the other homologous chromosome.
This increases genetic variation.

13. Identical diploid cells
Comparing Mitosis and Meiosis
Mitosis
Meiosis
# of chromosomes in G1
46 (2n)
# of chromosomes after S 92
# of chromosome divisions
1 division
2 divisions
# of chromosomes in final cell
23 (n)
# of final cells 2
♂= 4 sperm cells
♀= 4 egg cells
Type of final cell
Identical diploid cells
Unique haploid cells