1. Friday
Unit 6 Notes: Meiosis-2

2. (1) Meiosis 2 Events: DNA condenses. Sister Chromatids Line Up.
Sister Chromatids separate.
End up with 4, 1n cells!

3. (2) Genetic Information:
Mitosis:
Start 2n  “diploid”
End 2n  “diploid”
Meiosis:
End 1n  “haploid”

4. (3) Meiosis-2 Stages: Prophase-2 Metaphase-2 Anaphase-2 Telophase-2
Cytokinesis  Not really part of Meiosis, but necessary!

5. (4) Prophase-2:
Centrioles & Spindle Fibers prepare (again).

6. D d D d a A b B a A b B

7. (5) Metaphase-2:
Sister Chromatids line up at the Metaphase Plate according to each other’s centromeres.

8. Sister Chromatids @ Metaphase Plate
Centromere
Cell Membranes A a a A D d d D b B B b
Sister Metaphase Plate

9. (6) Anaphase-2: Sister Chromatids separate. Law of Segregation:
Alleles are separated so that each sperm/egg only has 1 allele/gene.
Result = A sperm/egg with ½ the DNA
Independent Assortment:
Alleles are separated completely randomly.
Alleles separate w/o regard to other genes.

10. Randomly & Independently Separated Chromosomes
Cell Membranes a A a A d D d D b B B b
Randomly & Independently Separated Chromosomes

11. (7) Telophase-2: Chromosomes unwind back to regular DNA.
Nucleus reforms around DNA.

12. Reforming Nucleus d B D b a A b b B D d
Cell Membrane a A

13. (8) Cytokinesis: Cytoplasm pinches off.
Cell membrane closes around each of the 4 daughter cells.

14. Haploid Daughter CellsB D a A b
Haploid Daughter Cells B b d A D a