1. Meiosis Chapter 11 Sec. 4

2. Meiosis Reduces # of chromosomes to half Diploid (2n) to haploid (1n)

3. Meiosis Produces gametes = sperm and egg Each contains 23 chromosomes

4. Stages of Meiosis Goes through G1, S, G2 Basically go through mitosis twice 1 cell divides into 4 cells with half of information

5. Meiosis I Prophase 1 Metaphase 1 Anaphase 1 Telophase 1 and cytokinesis 1

6. Prophase 1 DNA coils into chromosomes Spindle fibers appear Nuclear envelope disappears

7. Prophase 1 Homologous pairs form tetrads Crossing over can occur here –Exchange of genetic material between chromosomes

8. Prophase 1 Crossing over results in genetic recombination –Produces new genes

9. Metaphase 1 Tetrads line up along the equator of cell Kinetochore attach to centromeres

10. Anaphase 1 Kinetochore pulls tetrads apart to separate poles Randomly separates= independent assortment Provides variation

11. Telophase 1 Chromosomes reach separate ends Cytokinesis begins

12. Meiosis 1 Original cell produces two new cells Each contains one chromosome= haploid

13. Meiosis 2 Second stage of meiosis –Prophase 2 –Metaphase 2 –Anaphase 2 –Telophase 2 and Cytokinesis

14. Prophase 2 Spindle fibers form Nuclear envelope disappears

15. Metaphase 2 Chromosomes move to middle of cell

16. Anaphase 2 The chromatids separate and move towards opposite poles

17. Telophase 2 Nuclear membrane forms Cytokinesis occurs Results in 4 new cells each with haploid #

18. meiosis

19. Gametes In animals meiosis = gametes Occurs in testes and ovaries Only in sex chromosomes

20. Spermatogenesis Production of sperm cells

21. Oogenesis Production of eggs

22. Asexual Reproduction Production of offspring from one parent –Mitosis, binary fission or budding –Genetically identical

23. Sexual Reproduction Production of offspring through meiosis and union of sperm and egg –Genetically different from parents