1. Chromosomes

2. Please immediately take out:
1. Chromosome/meiosis Notes
2. Mitosis/cell division Notes
3. HW (SG#4-7)
4. Blank Piece of paper(lined or unlined)

4. How much DNA do you have? Human DNA contains 3 billion base pairs
The DNA inside one of your cells is 6 feet long

5. How does it all fit then?
DNA is wrapped up very tightly into structures we call chromosomes

6. How does DNA get wrapped into chromosomes?
Chromosomes are made of chromatin.
DNA + histone proteins = Chromosome

8. Basic Structure(READ ONLY)
Chromosomes are only visible when a cell is going to divide, so we usually see them in their double-stranded form
The halves of a double-stranded chromosome (chromatids) are identical to each other because the DNA in the original chromosome replicated prior to cell division

11. How many chromosomes do humans have?
In every non-sex cell (diploid cell) in your body you have 46 chromosomes (diploid #) from mom and 23 from dad
23 chromosomes + 23 chromosomes = 46 chromosomes
from mom from dad

12. Skin Cell

15. Types of Chromosomes Heart Cell Skin Cell
Humans have 2 sex chromosomes in every non-sex cell of their body (DNA that determines if a person will be male or female)
X X = female X Y = male
Autosomes -- all of the other chromosomes
Humans have 44 autosomes in every non-sex cell of their body
44 autosomes
+ 2 sex chromosomes
46 chromosomes Total
Heart Cell
Skin Cell

16. Diploid or haploid
Haploid = Half= 42
Diploid = Double=84

17. Autosomes
Sex Chromosomes

20. Sex Cells aka Gametes Female sex cell (gamete) = egg
Male sex cell (gamete) = sperm
Every sex cell (gamete) contains only 23 chromosomes (22 autosomes and 1 sex chromosome)
_________ 23 23

21. Skin Cell

22. Other Organisms
Different species contain different #s of chromosomes
Organism # in non-sex cell (diploid) #in sex cell (haploid)
Lion ___ 19
Gold fish ___
Chicken 78
Cow
Ants 2
Chimp 48
Adders tongue 38 47 39 60 1 24
2000

23. Sperm (_______)
haploid
Egg (_______)
haploid
Mom
Dad
Zygote (_______)
Diploid)

24. A Kangaroo has 12 chromosomes in every diploid cell of its body
A Kangaroo has 12 chromosomes in every diploid cell of its body. Draw a picture of what the sperm and egg would look like. Draw a picture of the zygote

25. Sperm (Haploid)
Egg (Haploid)
Zygote (Diploid)

26. A Fruit Fly has 8 chromosomes in every diploid cell of its body
A Fruit Fly has 8 chromosomes in every diploid cell of its body. Draw a picture of what the sperm and egg would look like. Draw a picture of the zygote

27. Homologous Chromosomes
Homologous chromosomes have DNA that codes for the same genes. Has same genes in same locations, but different versions of the genes.
MOM
DAD

29. Duplicated Unduplicated
Homologous
Chromosomes
Mom
Dad

30. Draw and explain the following chromosome, homologous chromosome and tetrad(pg. 162)
Hair color
Hair color
Ear lobe shape
Ear lobe shape

31. Sexual Reproduction How am I here?
When 1 sperm fertilizes 1 egg it produces a cell called a zygote with 46 chromosomes
Sexual Reproduction

32. Chromosomes replicate
Meiosis- formation of haploid gametes
(summarized version)
Chromosomes replicate
1st cell division
2nd cell division

33. Males- 4 (haploid) sperm cells are produced.
4 (Humans 46)
2 (Humans 23)

34. One egg and 3 polar bodies
Female
One egg and 3 polar bodies

35. Crossing over/Meiosis Video

36. Crossing over
When homologous chromosomes form tetrads in meiosis I, they exchange portions of their chromatids in a process called crossing over.
Crossing-over produces new combinations of alleles/increased genetic variety
Crossing-over occurs during meiosis. (1) Homologous chromosomes form a tetrad. (2) Chromatids cross over one another. (3) The crossed sections of the chromatids are exchanged.

38. Crossing over animation

39. 13.3 Meiosis! M G2 S G1

40. 13.3 Meiosis! M G1 G2 S Homologous Chromosomes Synapsis Crossing Over
Tetrad

41. 13.3 Meiosis! M G2 S G1

42. 13.3 Meiosis! MI G2 S G1

43. 13.3 Meiosis! MI G2 S G1
Diploid Or
Haploid?

44. 13.3 Meiosis!
MII G2 S G1

45. THE “ART” YOU ARE ABOUT TO VIEW SHOULD NOT EVEN BE CALLED “ART” AND IS OF SUCH POOR QUALITY AND A LOW TECH NATURE IT SHOULD ONLY BE VIEWED BY A MATURE AUDIENCE….ONCE (ok so a little hyperbole-but it will help with your video)

46. Independent Assortment video https://www. youtube. com/watch

54. Why do females only produce one egg during meiosis?
It needs to have all of the nutrients to support life and must have enough energy to travel to the uterus.
Do females perform meiosis throughout their lifetime?
No, they are born with all of the eggs they will ever have!

55. Meiosis- Division of sex cells
What is meiosis?
Formation of gametes.
What are gametes?
sperm and egg.

56. Are gametes haploid or diploid?
Haploid (Half the # chromosomes as a body cell).
Humans have 23 chromosomes in their gametes
How many alleles for each gene do gametes have?
Gametes have one allele for each gene.

57. How many cells are produced from one meiosis division?
4 sperm and one egg

59. Mitosis VS MEIOSIS Mitosis Body cells 2 Diploid 4. 46 Meiosis
Sex Cells 4
Haploid
4. 23
1. What kind of cells are produced?
2. How many cells are produced?
3.Are they haploid or diploid?
4. Number of chromosomes in humans?

60. Gamete Formation
In male animals, meiosis results in four equal-sized gametes called sperm.
Meiosis produces four genetically different haploid cells. In males, meiosis results in four equal-sized gametes called sperm.

61. Gamete Formation
In many female animals, only one egg results from meiosis. The other three cells, called polar bodies, are usually not involved in reproduction.
Meiosis produces four genetically different haploid cells. In females, only one large egg cell results from meiosis. The other three cells, called polar bodies, usually are not involved in reproduction.