1. Which animal will stay warm longer, a mouse or an elephant?

2. Define in your own words (p. 275)
Meiosis
Diploid
Haploid
Gamete
Crossing Over
Chromosomes

3. Draw a chromosome. Explain what a chromosome is.
Daily Question
Draw a chromosome. Explain what a chromosome is.
Why is crossing over important?

4. Eukaryotic Chromosomes
All eukaryotic cells store genetic information in chromosomes
Human body cells have 46 chromosomes or 23 identical pairs

5. Chromosomes in Dividing Cells
Two sides of a chromosome are called chromatids & are held together by the centromere
Called Sister Chromatids

6. Chromosome Structure
Chromosomes contain DNA and Protein packed together to form chromatin.
Chromatin is made of DNA that is wrapped around the protein, histones.
Histone and DNA forms clusters called nucleosomes.

7. The Y Chromosome Decides
Boy or Girl?
The Y Chromosome Decides
Y - Chromosome
X - Chromosome

8. Daily Question
Explain the differences between homologous chromosomes and sister chromatids.

9. Cell Reproduction

10. Meiosis Formation of Gametes (Eggs & Sperm)

11. Facts About Meiosis Two meiotic divisions --- Meiosis I and Meiosis II
Original cell is diploid (2n)
Four daughter cells produced that are haploid (1n)

12. Meiosis: Two Part Cell Division
Sister
chromatids
separate
Meiosis I
Meiosis II
Homologs
separate
Diploid
Diploid
Haploid

13. Meiosis I: Reduction Division
Nucleus
Spindle
fibers
Nuclear
envelope
Early Prophase I
(Chromosome number doubled)
Late Prophase I
Metaphase I
Anaphase I
Telophase I (diploid)

14. DNA replication occurs
Nucleus
Spindle
fibers
Nuclear
envelope
Interphase
Before Meiosis Begins
DNA replication occurs

15. Prophase I
Crossing over occurs- homologous chromosome- Form Tetrad

16. Tetrads Form in Prophase I
Homologous chromosomes (each with sister chromatids)  
Join to form a TETRAD

17. Crossing-Over
Pieces of genes are exchanged

18. Homologous Chromosomes During Crossing-Over

19. 1. Crossing-over occurs during: A. anaphase 1 B. Metaphase 1 C
1. Crossing-over occurs during: A. anaphase 1 B. Metaphase 1 C. Prophase 1 D. Prophase 2 2. Which of the following cells undergo meiosis? A. Sperm Cells B Liver Cells C. Unicellular organisms D. All of the above

20. Explain all parts of a chromosome, in words and drawings.
Quiz
Explain all parts of a chromosome, in words and drawings.
Define diploid, chromatin,
sister chromatids, and centromere.
Extra Credit: What phase is technically not part of meiosis? Why?

21. Homologous pairs of chromosomes align along the equator of the cell
Metaphase I
Homologous pairs of chromosomes align along the equator of the cell

22. Anaphase I Homologs separate and move to opposite poles.
Sister chromatids remain
attached at their centromeres.

23. What is the difference between Metaphase and Anaphase?
Break
What is the difference between Metaphase and Anaphase?
What is the job of the centrioles?

24. Telophase I Nucleus reassembles. Spindle fibers disappear
Cytokinesis divides cell into two.

25. What is the difference between Interphase and Prophase?
Break
What is the difference between Interphase and Prophase?

26. Explain what occurs in Meiosis I, in your own words.
Daily Question
Explain what occurs in Meiosis I, in your own words.

27. Meiosis II Meiosis II produces gametes with
Only one homolog of each chromosome is present in the cell.
Gene X
Meiosis II produces gametes with
one copy of each chromosome and thus one copy of each gene.
Sister chromatids carry
identical genetic
information.

28. Meiosis II: Reducing Chromosome Number
Prophase II
Metaphase II
Telophase II
Anaphase II
4 Identical haploid cells

29. Prophase II Nuclear envelope disappears. Spindle forms.
Half the number of chromosomes as original in each cell

30. What is the difference between Prophase I and Prophase II?
Break
What is the difference between Prophase I and Prophase II?
What is the difference between the cells at the end oogenesis and spermatogenesis?

31. At the very end of meiosis II each cell has 23 chromosomes.
Daily Question
At the very end of meiosis II each cell has 23 chromosomes.
How many chromosomes are created during Interphase?
How many chromosomes does the cell have at the very start of Prophase I?

32. Metaphase II
Chromosomes align
along equator of cell.

33. Anaphase II Sister chromatids separate and move to opposite poles.
Equator
Pole
Sister chromatids separate and move to opposite poles.

34. What is the difference between Anaphase I and Anaphase II?
Break
What is the difference between Anaphase I and Anaphase II?

35. Telophase II
Nuclear envelope assembles.

36. Cytokinesis II Gametes (egg & sperm) form
Four haploid cells with one copy of each chromosome
Different combinations of different genes
Hybrid offspring

37. Meiosis results in _____
A. 2 haploid daughter cells B. 4 haploid daughter cells
C. 2 diploid daughter cells D. 4 diploid daughter cells

38. The picture depicts what stage of meiosis?        
A. Prophase 1 B. Anaphase 1
C. Metaphase 1 D. Metaphase 2

39. Name of Process in Gametes
Egg: Oogenesis
Formation of 1 true egg and 3 polar bodies
Sperm: Spermatogenesis
Formation of 4 true sperm cells

40. Winter Break Extra Credit
Make an information pamphlet about one specific genetic diseases.
The following must be included:
What is the disease? What does the disease do to the body it is affecting?
When was the disease discovered? Who discovered it?
What type of mutation causes the disease?
What are the tests to see if a person has the disease?
How many people get this disease?
Any other important information people need to know about the disease.
Pictures

41. Holiday Science If you don’t bring something you can’t eat anything!
Friday December 19, 2008
Bring some food to share with the class. It can be anything you enjoy!
If you don’t bring something you can’t eat anything!