1. If the sperm and egg had a full set of 46 chromosomes, how many would the zygote (fertilized egg) have? 46 92 46

2. What would happen to the chromosome number each generation if the sperm and egg had a full set of chromosomes?
It would double!
Sperm + egg
Sperm + egg 92
Sperm + egg
184

3. MEIOSIS Cell division that produces eggs and sperm
the process of cell division in which the chromosome # is cut in half

4. 46 46 diploid # of chromosomes meiosis sperm egg 23 23 monoploid # of
male female
diploid # of chromosomes
meiosis
sperm egg
monoploid # of
chromosomes fertilization zygote 46 (diploid #)

5. meiosis and fertilization keep the # of chromosomes constant from generation to generation

6. mitosis meiosis my toe eggs and sperm
What kind of cell division occurs in the embryo?

7. Where does meiosis occur in humans?

9. Mitosis

10. Meiosis
synapsis

11. disjunction

14. meiosis
Diploid 2n
monoploid n

15. 4 3 2 1
1 (5)
4 (8)
3 (7)
2 (6)

16. 1 7 3 4 6 2 5 8

17. Meiosis animation

18. synapsis - coming together of homologous copied chromosomes - they line up in pairs

19. Meiosis
synapsis

21. It increases genetic diversity
crossing over
– the exchange of segments between chromatids during synapsis
Why is this important?
It increases genetic diversity

22. Crossing Over

23. (e.g. red hair and freckles)
Why are some traits always inherited together?
(e.g. red hair and freckles)

24. What effect does linkage have on independent assortment?
Gene Linkage – 2 or more genes located on the same chromosome; these genes are inherited together
linkage group - all the genes that are on the same chromosome
What effect does linkage have on independent assortment?

25. What effect does crossing over have on linkage?

26. Crossing over breaks linkage groups
crossing over is an exception to linkage

28. Place the letters in the correct positions on each chromo-someb b B B F f F f b b B B F f F f b b B B F f F f

34. Mitosis vs. Meiosis

35.       

36. Mitosis Meiosis         

37. MITOSIS
MEIOSIS
chrom.number chrom. number
stays the same cut in half
forms body cells forms sex cells from from body cells gonad cells
(primary sex cells)
2 kinds of each 1 kind of each
chrom. in each cell chrom.in each cell
(2 sets) (1 set)

38. Comparison of Meiosis and Mitosis
Homologous Homologous Chromosomes Chromosomes
do not pair up pair up
no crossing over crossing over
1 division divisions
forming 2 cells forming 4 cells
new cells get the same cells get one half
# and type of the # and type of chrom. chromosome (1 of each homologous pair)
MITOSIS
MEIOSIS

40. How does meiosis and fertilization increase genetic variation?

41. How does meiosis and fertilization increase genetic variation?
crossing over
random segregation of chromosome pairs
fertilization
many different possible combinations of genes in sperm and egg

42. Why is genetic variation important?
If the environment changes some organisms may have the variations (inherited characteristics) needed to survive the change
Variation creates new characteristics or new combinations of characteristics that help a species adapt to its environment

43. How is meiosis different in males and females?

45. Polar body

46. Why do women only produce 1 egg from every primary sex cell whereas men produce 4 sperm cells from every primary sex cell?

47. Why are polar bodies important?
(What is the function of a polar body?)

48. Zygote (fertilized egg)

49. 2 cells
4 cells
8 cells
Where is this process occuring?

50. Where is the embryo getting the nutrients
it needs as it passes down the oviduct?

51. Why are polar bodies important?
(What is the function of a polar body?)

52. Function of a polar body
Removes the extra set of chromosomes without taking away much cytoplasm from the egg
…So the egg can be as large as possible and store nutrients for the embryo to use before the placenta is formed

53.
Fertilization activates egg
Start at 4:08)

54. Oogenesis Spermatogenesis
1 egg cell produced; 4 sperm cells produced
3 polar bodies no polar bodies produced produced
production occurs during production during development; occurs finishes during throughout a fertilization male's lifetime

55. spermatogenesis

56. oogenesis

57. Draw the chromosomes in each of the empty cells

58. Draw the chromosomes in each of the empty polar bodies and the egg

61. Eggs Sperm large, round small - head, acrosome, middlepiece, flagellum
stored food – no stored food
yolk (for developing
animal)
sessile motile
cytoplasm, almost no cytoplasm, mitochondria mitochondria left outside fertilized egg

65. Kissing or Fighting?