1. Sexual Reproduction and Meiosis
Chapter 11

2. Insert Good Title Here….
Gametes
Somatic Cells
Germ Line Cells
Zygote
What does Meiosis do and Why is it important?

3. Sexual Life Cycles Algae and Fungi Most Animals
Some plants and some algae
Figure 11.2

4. What Makes Meiosis Different from Mitosis?
Synapsis
Crossing over and Recombination
Separation during Anaphase 1
2 divisions with only 1 replication stage

5. Parts of Meiosis Prophase 1 Metaphase 1 Anaphase 1 Telophase 1
Prophase II
Metaphase II
Anaphase II
Telophase II

6. Prophase I DNA condenses and Chromosomes become visible
Synapsis Occurs
Crossing Over Occurs
Chiasmata

7. Metaphase 1 Homologous Chromosomes line up on Metaphase Plate
Microtubules attach to kinetochores of each homologue (but not individual chromatids)

8. Anaphase 1 Homologues are pulled apart…what about chromatids?
Independent Assortment

9. Telophase 1 Cells Complete Separation and nuclear envelope reforms
Cytokinesis may or may not occur

10. Prophase II
Nuclear Envelope Breaks Down
New Spindle Forms

11. Metaphase II Chromosomes Line up along Metaphase Plate
Microtubules attach to each sister chromatid

12. Anaphase II
Sister Chromatids are pulled apart

13. Telophase II
Nuclear Envelope Reforms
Cytokinesis Follows

14. Problems with Meiosis
Nondisjunction
Aneuploid Gametes

15. Key Points of Meiosis
1. Pairing of homologues and crossing over that joins maternal and paternal homologues
2. Co-segregation of sister centromeres during anaphaseI due to maintenance of sister chromatid cohesion as sister centromeres
3. The attachment of sister kinetochores to the same pole in meiosis I and to opposite poles in mitosis
4. Suppression of replication between two meiotic divisions