Meiosis-

1. Meiosis- • Process that produces haploid gametes from diploid cells • Reduces the number of chromosomes to half

2. Gametes • Reproductive cells • Male- sperm cells • Female- egg cells (ova)

3. Diploid- • The total number of chromosomes (2N) • All non-reproductive cells- • Both sets of homologous chromosomes • Ex. drosophila (fruit fly) = 8 • Ex. human = 46

4. Haploid (monoploid)- • ½ the total number of chromosomes (1N) • Only gametes (reproductive cells) • Single set of chromosomes • Ex. drosophila = 4 • Ex. human = 23

5. Two division process • Meiosis I • Stages of 1st cell division • Meiosis II • Stages of 2nd cell division • pp 162-163

6. Two division process • Meiosis I • Synapsis- the pairing of homologous chromosomes. (does not occur in mitosis) • Random

7. Two division process • Meiosis I • Tetrad- each pair of homologous chromosomes (4 replicated chromatids) (page 162) • Crossing Over- when chromosomes that make up a tetrad exchange parts of their chromatids

8. Two division process • Meiosis II • Basically just like mitosis • 2 haploid cells will result in 4 haploid cells

9. Meiosis in Males • Spermatogenesis- • One diploid cell results in the formation of 4 sperm cells • p 164

10. Meiosis in Females • Oogenesis • One diploid cell results in the formation of 1 egg cell and 3 polar bodies • p 164

11. Mitosis vs Meiosis

12. Video- “The Meiosis Square Dance” • Introduces the process of meiosis by- • Presenting the chromosomes as characters at a square dance held inside a fruit fly. • Dino and Dina Chromosome coil up, duplicate, cross over, and separate as they dance their way through interphase, prophase, metaphase, anaphase, telophase, and cytokinesis.

13. All Images- Clip Art