1. Meiosis pp

2. Double Mitosis Results in haploid cells (n)  gametes
2n ”4n”  (2) 2n  (4) n
Two stages of meiosis
Meiosis I
Meiosis II
CLIP

3. 1. Similar to the phases of mitosis 2. 2n  “4n”  (2) 2n 3
1. Similar to the phases of mitosis 2. 2n  “4n”  (2) 2n 3. separating homologous chromosomes
MEIOSIS I

4. MEIOSIS I (continued)
Two important things occur in meiosis I that do not occur in mitosis
crossing over and independent assortment

5. MEIOSIS I (continued)
Synapsis: during prophase I chromosomes line up with homologues via corresponding genes to make a tetrad
Crossing-over: random exchange of genetic material during synapsis
homologous pairs overlap and twist on
each other (not always the exact same spot!!)
Independent assortment: random separation of the homologous chromosomes occur during anaphase I

6. MEIOSIS II Begins right after meiosis I
1. (2) 2n  (4) n ; 4 haploid cells
2. separating into single chromatids
MEIOSIS II
CLIP

7. Meiosis = the formation of Gametes
Spermatogenesis (testes): males produce sperm cells
Oogenesis (ovaries): females make eggs and produce one egg and 3 polar bodies (useless) at the end of one cycle of meiosis- occurs only at ovulation