1. Aim: How does sexual reproduction occur?

2. Look at the end result and what’s inside!!

3. MEIOSIS
Produces daughter cells that have half the number of chromosomes as the parent cell.

4. Meiosis enables organisms to reproduce sexually.
Gametes (sperm and eggs) are haploid.

5. Gametogenesis
Cell division that produces gametes

6. Meiosis involves two divisions producing a total of four daughter cells

7. 2 stages: Meiosis I, Meiosis II
1 2 4 cells with half the normal # of chromosomes
2 stages: Meiosis I, Meiosis II 23 23 23
MEIOSIS II 46
MEIOSIS I 23 23 23

9. Meiosis I
Contains all phases of mitosis (IPMAT)

11. Meiosis II
No interphase (PMAT)
No replication of chromosomes

14. Meiosis
in males
Spermatogenesis
All 4 new cells become sperm cells
Testes

15. Meiosis in females Oogenesis (in ovaries)
1 egg, 3 polar bodies (break down)
Meiosis in
females

16. The polar bodies eventually disintegrate, leaving 1 ovum cell (egg) with haploid chromosomes.
In oogenesis, 4 daughter cells are produced, but 3 are a lot smaller. We call them polar bodies.
This normally happens once a month.

18. So, what is the difference between mitosis and meiosis?

19. Mitosis produces 2 identical daughter cells with the same number of chromosomes as the parent.
Meiosis produces 4 haploid cells (half the number of chromosomes as the parent it came from).