1. HAPPY NEW YEAR!! Please grab the paper from the entry table.
You will also need scissors, glue and your journal.
PHONES IN THE POCKETS PLEASE

2. Why do you and your siblings look different?

3. How did the difference in our DNA occur?
If we share the same parents?

4. Let’s review
How do we go from one single cell to an multi-cell organism?

5. Let’s review: The cell cycle (cell division)
Mitosis

6. Mitosis only creates cells to help our body grow
In these cells they have identical DNA

7. What is Meiosis?
Form of cell division in which the number of chromosomes is reduced by half (haploid) to produce sex cells (gametes) used in fertilization.
Results in variability of genetic information
Eggs or sperm

8. There are 2 category of cells in our body: somatic and sex cells
Somatic Cells(body cells)
Any cells that helps in the growth of an organism
Is diploid (2n)
Example: skin, muscle, blood cells
Sex Cells (Gametes)
Eggs and Sperm
Reproductive cells of an organism
Is haploid (n)

9. Mitosis vs. Meiosis
With your partner create a t-chart in your notebook and come up with as many differences between Mitosis and Meiosis (use the diagram to help you)

10. Mitosis Vs. Meiosis (If you don’t have this information copy it into your notebook)
Division of somatic/body cells
1 division = 2 cells
Daughter cells identical
Diploid cells (2N) =46
Chromosome # identical to parent cell
Used for growth and repair
Meiosis
Division of gametes (sex cells—eggs or sperm)
2 divisions = 4 cells
Daughter cells different (crossing over; independent assortment)
Haploid cells (N)=23
Chromosome # half of parent cell
Used for reproduction

11. How is Meiosis Different?
There are 2 divisions in meiosis
Meiosis I and meiosis II
The result is 4 daughter cells instead of 2
In meiosis II, the DNA is not replicated again (No interphase)
The ending number of chromosomes is 23 in humans (egg has 23 and sperm has 23). This is haploid (n).

12. How many chromosomes? 38 46 20
200 78

13. Why do you think sperm and egg are haploid? (have 23 chromosomes)

14. Meiosis clip https://www. youtube. com/watch
Meiosis clip Stop here Monday.

15. Tuesday, January 3, 2017
Please grab the papers from the entry table. These are going to be vocabulary flashcards for this unit.
Grab some scissors and begin cutting the flashcards. Be ready when the bell rings.
PHONES IN THE POCKETS 

16. Use your notes from yesterday to write the definitions of the following words (write the definition on the back of the card).
Somatic Cells
Sex Cells
Gametes
Haploid
Diploid
Daughter Cells

17. Oogenesis & Spermatogenesis
After meiosis the cells have a few more steps before they are eggs & sperm
Spermatogenesis: 4 sperms are created after the cell is modified to have flagella
Oogenesis: eggs need more cytoplasm and organelles so the cytoplasm of 3 of the cells is absorbed by 1. This results in 1 large egg cell and 3 polar bodies that get reabsorbed by the body.

18. Spermatogenesis and Oogenesis

19. Homologous chromosomes
Chromosomes that share the same gene location for a particular trait

20. Tetrad
- Structure containing 4 chromatids that form during meiosis.

21. Crossing over
Homologous chromosomes exchange portions of their chromatids.
Results in new combinations of genes and different chromatids
Happens in PROPHASE

22. Homologous chromosomes

23. How does meiosis promote genetic variation?
Independent Assortment - Each chromosome is randomly sorted independently of other chromosomes
A human who has 46 chromosomes, there are around 8 million possible combinations for a sperm or egg cell.

24. How does meiosis promote genetic variation?
Crossing Over – pairs of homologous chromosomes swap the same segment of genes, forming a chromosome that has some of mom’s and some of dad’s DNA combined.

25. How does meiosis promote genetic variation?
Random Fertilization – the fertilization of an egg and sperm is completely random

26. Zygote
A diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

27. Sexual Reproduction
Reproduction that involves the exchange of genetic material between two organisms
Meiosis

28. Asexual Reproduction
A method of reproduction where a single parent gives rise to two genetically identical offspring, w/o the use of gametes.
Mitosis

29. With your table group, quiz each other using your flashcards
With your table group, quiz each other using your flashcards. You will have a quiz on Friday!!!  STOP HERE TUESDAY

30. Wednesday, January 4, 2017 Please grab the papers at the entry table.
You will also need scissors, glue, colored pencils and your journal.
Please be ready to go when the bell rings.
PHONES IN THE POCKETS

31. Can you determine which children belong to which couple
Can you determine which children belong to which couple? Genetic variation is important in creating individuals!
From Pearson Education

32. Answer: The first and last picture belong to couple 1
Answer: The first and last picture belong to couple The middle pictures belong to couple 2.

33. Steps in Meiosis
Meiosis I: Prophase I Metaphase I Anaphase I Telophase I Meiosis II: Prophase II Metaphase II Anaphase II Telophase II

36. Prophase I DNA condenses and chromosomes become visible.
Crossing over occurs
Tetrad

37. Metaphase I
Homologous chromosomes line up along the metaphase plate(equator).

38. Anaphase I
Spindle fibers move homologous chromosomes to opposite sides of the cell.

39. Telophase I & Cytokinesis
Nuclear membrane reforms and cytokinesis occurs
Result is two diploid daughter cells.

40. Prophase II
Nuclear membrane breaks apart.
Spindle fibers form

41. Metaphase II
Chromosomes line up along the equator, not in homologous pairs.

42. Anaphase II
Chromatids separate

43. Telophase II Nuclear membrane reforms; cytoplasm divides
Result is 4 haploid cells.

44. Practice Questions

45. Practice Question
What inference can be made from the diagram shown?
A. The sperm will have double the amount of chromosomes as the parent cell.
B. None of the cells made copies of their chromosomes
C. The sperm will have half the number of chromosomes as the parent cell.

46. The diagram above shows the process of meiosis
The diagram above shows the process of meiosis. The segregation that occurs during meiosis results in a — A decrease in the total number of cells per organism B reduction in the number of chromosomes per cell C group of genetically identical cells

47. Compare to mitosis, Meiosis will result in
A. 2 Daughter cells B. 4 Daughter Cells C. Less number of daughter cells than mitosis

48. What is the name of this process?
Mitosis
DNA replication
Crossing over

49. Which of the following is NOT a result of Crossing over?
Both chromosomes with identical genes
New combination of genes in each chromosome
Genetic variability

50. Which process of Meiosis is represented by “X”?
Mitosis
Meiosis I
Meiosis II