1. Chapter 13 ~ Meiosis and Sexual Life Cycles
Can you pick out the “offspring” for each couple?

2. Can you pick out the “offspring” for each couple?

3. In a literal sense, children do not inherit particular physical traits from their parents
It is genes that are actually inherited
In a literal sense, children do not inherit particular physical traits from their parents
It is genes that are actually inherited

4. Genes are the units of heredity
Genes are segments of DNA
Genes have specific loci on a certain chromosome
One set of chromosomes is inherited from each parent
Reproductive cells called gametes (sperm and eggs) unite, passing genes to the next generation

5. Heredity The transmission of traits from parents to offspring.
Comment - Humans have been aware of heredity for thousands of years.

6. Heredity
The transmission of traits from parents to offspring.
Comment - Humans have been aware of heredity for thousands of years.
Genetics
The scientific study of heredity.
Comment - Genetics is only about 150 years old.

7. Remember, genes are on the chromosomes
Mitosis produces two cells with the same number of chromosomes as the parent cell.
Remember, genes are on the chromosomes

8. Mitosis of a diploid cell (2n) produces: two. diploid (2n). daughter
Mitosis of a diploid cell (2n) produces: two diploid (2n) daughter cells.

9. If two diploid cells went on to participate in sexual reproduction,

10. their fusion would produce a tetrapoloid (4n) zygote

11. Female 46 Male 46
egg sperm 46
Zygote 92
mitosis mitosis

12. What is the answer?

13. Meiosis To reduce the number of chromosomes by half.
Prevents doubling of chromosome numbers during sexual reproduction.

14. Homologue Chromosomes -
Bio I review words:
Homologue Chromosomes -
Sex Chromosomes -
Autosomes -

15. Pair of homologous
chromosomes
Centromere
Sister
chromatids

16. Bio I review words:
Diploid # -
Haploid # -

18. Bio I review words:
Diploid Cell (2n) -
Haploid Cell (n) -

19. Homologue Chromosome -
Bio I review words:
Homologue Chromosome -

20. Key Maternal set of chromosomes (n = 3) 2n = 6 Paternal set of
Two sister chromatids
of one replicated
chromosomes
Centromere
Two nonsister
chromatids in
a homologous pair
Pair of homologous
chromosomes
(one from each set)

21. Bio I review words:
Tetrad -

23. Individual chromosomes replicate
Interphase
Individual chromosomes replicate

24. chromosomes seek out their homologue to form tetrad
Prophase I
chromosomes seek out their homologue to form tetrad
crossing over occurs here

25. CROSSING OVER

26. tetrads line up on metaphase plate
Metaphase I
tetrads line up on metaphase plate

27. It is random chance as to which chromosome is pulled to a side.
Anaphase I
tetrads move apart
It is random chance as to which chromosome is pulled to a side.

29. Two nuclear envelopes begin to surround the chromosomes
Telophase I
Two nuclear envelopes begin to surround the chromosomes

30. No DNA synthesis occurs.
Interkinesis
No DNA synthesis occurs.
May last for years, or the cell may go immediately into Meiosis II.
May appear similar to Interphase of Mitosis.

31. Prophase II
dyad (1/2 tetrad)

32. dyad (1/2 tetrad) line up on the metaphase plate.
Metaphase II
dyad (1/2 tetrad) line up on the metaphase plate.

33. dyads (1/2 tetrad) are separated into individual chromatids
Anaphase II
dyads (1/2 tetrad) are separated into individual chromatids
Sister chromatids end up on each side of the cell

34. nuclear envelope forms
Telophase II
nuclear envelope forms
cytoplasm divides
4 haploid cells are formed

36. MEIOSIS

37. MEIOSIS

38. of meiosis & fertilization
Alternation
common to all
organisms that
reproduce sexually
of meiosis & fertilization

39. these events varies between kingdoms
Alternation
the timing of
these events varies between kingdoms
of meiosis & fertilization

40. gametes only are haploid
Animals
gametes only are haploid
meiosis for production of gametes

41. multicellular organism is diploid
Animals
multicellular organism
is diploid
meiosis for production of gametes

42. WHAT?
Sexual
Life Cycles

45. Fungus
gametes are haploid
zygote forms

46. meiosis before the offspring develops
Fungus
zygote is diploid
meiosis before the offspring develops

47. Fungus
offspring are haploid

48. multicellular organism is haploid
this produces haploid cells
that divide
by mitosis

49. Fungus
gametes by mitosis

57. 1 map unit = frequency % of crossing over

58. 1% = 1 map unit (centimorgan)

59. multicellular stages are
Plants & Algae
multicellular stages are
diploid & haploid

60. Plants & Algae
spores result from
meiosis
in sporophyte

61. multicellular haploid
Plants & Algae
spore then mitose
to form
multicellular haploid