1. Take 5: 11/9/11 What is a gene? What does meiosis produce?
What are the 2 divisions of Meiosis?

2. Meiosis Notes
Ch 10

3. Mendel's Principle of Genetics
1. Each organism must inherit a ________ copy of every gene from each of its parents.
2. Each organism produces its own gametes (aka sex cells) and each gamete has _____ set of genes.
single
one

4. Diploid vs. Haploid
A cell with two copies of each chromosome = __________ or _______
A cell with only one copy of each chromosome = ___________ or ______ 2n
diploid 1n
haploid

5. Diploid vs. Haploid
n = ___ 3
2n = 6

6. Number of Chromosomes in various organisms…

7. The two chromosomes of each pair in a diploid cell are called
One chromosome from Dad
One chromosome from Mom
The two chromosomes of each pair in a diploid cell are called
homologous
chromosomes

8. Each pair of homologous chromosomes has genes for the SAME traits
One chromosome from Dad
One chromosome from Mom
Each pair of homologous chromosomes has genes for the SAME traits
example: Chromosome pair #1 could code for eye color

9. So how do you get one chromosome from each parent?
Well, I think you already know that.

10. Fertilization, right?
Yep!

11. So that must mean that the sperm and egg cell are haploid.
Yep!

12. Are there any other cells in your body that are haploid?
Nope!

13. How do you make haploid cells?
Through meiosis

14. What’s that?
The way you produce a haploid cell from a diploid cell.

15. Definition:
Meiosis is the process in which the number of chromosomes in a cell is cut _______ due to a separation of homologous chromosomes in a diploid cell.
(2n  1n cell)
in half

16. Meiosis involves two distinct divisions
__________
Meiosis I
Meiosis II

17. Meiosis turns a single diploid cell into ________________
4 haploid cells
meiosis I
meiosis II

19. Prior to meiosis I: each chromosome is ______________
replicated
during
Interphase
copied
copied

21. Prophase I
Each chromosome pairs with the corresponding homologous chromosome to form a structure called a ________
There are ______ chromatids in a tetrad
tetrad
MOM
DAD
tetrad
four 1 2 3 4

22. Prophase I
In addition to pairing up and forming tetrads, they ALSO exchange portions of their chromatids in a process called _______________
The results in an ___________ of alleles to produce new ______________ of alleles
crossing over
exchange
recombination

23. NOTICE: This is one difference from mitosis
NOTICE: This is one difference from mitosis. In mitosis the chromosomes line up __________. In meiosis, they ______
individually
pair up
!!!

24. The pair of homologous chromosomes _________________________
Metaphase I
The pair of homologous chromosomes _________________________
Anaphase I
The homologous chromosomes randomly ________.
Telophase I
Two new cells are formed.
line up (in pairs) in the middle
separate

25. Now these two cells enter Meiosis II
UNLIKE THE FIRST DIVISION, these cells DO NOT UNDERGO ___________
replication

26. ______________________________
Prophase II:
______________________________
Metaphase II: ______________________________
Anaphase II: _____________________________
Telophase II:
________________ are produced.
spindles form & attach to centromeres
line up singularly in the middle
the sister chromatids separate
Four daughter cells

27. Gamete Formation
In MALES, haploid gametes produced are called ______. In plants it is called _______
In FEMALES, only ______ of the cells produced is involved in reproduction
AKA ______
Other three = _______________and are not used in reproduction
sperm
pollen
one
egg
polar bodies

28. Meiosis Makes HAPLOID sperm and egg cells
They skipped a few steps here

29. The Simplified Version:
MITOSIS
MEIOSIS

30. Let’s fill this in…
Mitosis
Meiosis

31. Typical Meiosis
Crossing over

32. Non-disjunction in Meiosis I
What happened here?

33. What does nondisjunction mean?
Non-disjunction in Meiosis II
What does nondisjunction mean?

34. Patterns of Heredity and Human Genetics
Chapter 12
Patterns of Heredity and Human Genetics

35. Pedigree
A graphic representation of genetic inheritance

36. Incomplete Dominance-phenotype is a mixture between those of 2 homozygous parents

37. Codominance- both alleles are expressed equally

38. Sex Linked Inheritance

39. Karyotype- normal male

40. Karyotype- Down Syndrome (Trisomy)

41. Karyotype –Turner Syndrome (monsomy)
Karyotype –Turner Syndrome (monsomy)