1. Notes – Meiosis

2. Meiosis Terms
Meiosis = the process of cell division that is used to produce gametes

3. Meiosis Terms Haploid = having one copy of each chromosome
Diploid = having two copies of each chromosome

4. Meiosis Terms

5. Meiosis Terms Chromosome = a molecule of DNA that contains many genes
Homologous chromosome = chromosomes that have the same genes but different alleles

6. The process of Meiosis

7. The process of Meiosis
The nuclear membrane breaks down and chromosomes condense from chromatin

8. The process of Meiosis
Homologous chromosomes line up in the middle of the cell

9. The process of Meiosis
Homologous chromosomes line up in the middle of the cell
Crossing over occurs: pieces of homologous chromosomes are exchanged

10. The process of Meiosis
Homologous chromosomes separate and the diploid cell divides into 2 haploid cells

11. The process of Meiosis
The two haploid cells each contain chromosomes that have two sister chromatids

12. The process of Meiosis
The sister chromatids in each haploid cell separate, the cells divide and 4 haploid cells are formed

13. The process of Meiosis
The sister chromatids in each haploid cell separate, the cells divide and 4 haploid cells are formed
Each of the 4 cells is genetically unique

14. Meiosis: Tradeoff Close your notebooks1 2
Close your notebooks
In your own words, tell your neighbor what happens…
Start with people by the door, then switch 3 4 5

15. Meiosis: Everybody Writes1 2
Close your notebooks
In your own words, write what happens… 3 4 5

16. Think … pair-share Why is this diagram misleading?
Ask students: Why is this diagram misleading?
Answer: the resulting cells are genetically unique due to crossing over rather than sets of two identical cells

17. Mitosis vs. Meiosis
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18. Mitosis vs. Meiosis
Pair-share: compare mitosis and meiosis [3]

19. Mitosis vs. Meiosis Similarities: Differences:
Diploid cells divide in both
Differences:
Meiosis results in 4 haploid cells whereas mitosis results in two diploid cells
Meiosis results in genetically unique cells whereas mitosis results in genetically identical cells
Meiosis involves homologous chromosomes pairing up and crossing over; mitosis does neither
Meiosis involves two rounds of cell division whereas mitosis involves one round of cell division