1. Meiosis Notes

2. 쓰지마: Bell’s First Halloween

6. How?
Segregation and Independent Assortment

7. …but first…
review…

8. What is chromatin?
Unwound DNA and proteins in the nucleus of a non-dividing cell.

9. What is a chromosome?
DNA and Protein in a coiled rod-shaped form that occurs during cell division

10. What is a chromatid?
One of two identical parts of a chromosome.

11. What is a centromere?
The constricted area of each chromatid that holds the chromatids together.

12. Mitosis White Board Activity
In the center of your table, on the white board, draw the phases of mitosis (after interphase to before cytokinesis).
Label each phase and the important structures.
Each person must draw or label.
You have 30 sec. to plan it, and 2min&30sec to draw it all.
Team with the most complete and clear mitosis wins a small, tasty prize.

13. What is a homologous chromosome?
쓰세요: One of two paired chromosomes, from each parent, that carries genes for a specific the same location.

14. What is the difference between diploid cells and haploid cells?
Diploid cells (body/somatic cells) are cells having two sets of chromosomes.(2n)
Haploid cells (sex cells/gametes) are cells containing only one set of chromosomes (1n)

15. What is mitosis?
The process in which two new cells with genetic material that is identical to that of the original cell
occurs in body cells (somatic or autosomal)

16. What is meiosis?
The process in which the # of chromosomes are reduced by half in new cells.
occurs in gametes (sex cells/eggs or sperm)

17. What are the stages of meiosis?
Meiosis I

18. Prophase I DNA coils into chromosomes.
Chromosomes line up with its homologous chromosomes. (synapsis)
Each pair of homologous chromosomes are called tetrads.
Crossing over may occur, portions of chromatids break and attach to adjacent chromatids on the homologous chromosome resulting in genetic variation (random switching).

19. Metaphase I Tetrads line up randomly in middle
(independent assortment), resulting in more genetic variation

20. Independent Assortment

21. Independent Assortment

22. Independent Assortment

23. Metaphase I Tetrads line up randomly in middle
(independent assortment), resulting in more genetic variation

24. Anaphase I
Random separation of homologous chromosomes

25. Telophase I
Chromosomes reach opposite ends of cells, cytokinesis begins.

26. (Meiosis II:) Prophase II -
chromosomes begin to move towards middle of the cell

27. Metaphase II
Chromosomes move to middle of cell

28. Anaphase II
Chromatids separate and move toward opposite polls of cell.

29. Telophase II
Nuclear membrane forms around the chromosomes in each of four new cells all with half the original of # of chromosomes.