Transcript Meiosis

Meiosis-A prelude to reproduction
I.
Terminology
• A.
karyotype
– 1. human 46
chromosomes
– 2. homologous pairs
– 3. diploid condition
– 4. note various sizes and
shapes
B. Chromatin
• 1. 1.8 meters
• 2. DNA
• 3. exists in a non-dividing cell
C. Relationship between chromatin and
chromosome
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1.
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4.
chromatin
chromosomes
histone proteins
nucleosome
D. Terms of chromosome structure
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4.
Monad
Dyad
Centromere
Sister chromatids
E. Homologous chromosome pairs
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1. definition
2. paternal vs. maternal
3. genes vs. alleles
4. synapsis
5. tetrad
6. sister vs. nonsister
chromatids
How many chromosomes do you see?
1.
2.
3.
4.
4
8
10
No clue
Enter answer text...
83%
17%
ue
0%
N
o
cl
10
8
4
0%
II. Review of mitosis
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A.
B.
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D.
E.
Prophase
Metaphase
Anaphase
Telophase
Products
III.
Meiosis overview
• A. Importance?
• B. Two separate
divisions
– Meiosis I reduction division
– Meiosis II “mitotic-like”
division
• C. Where does it occur?
D. What does meiosis
produce?
IV.
Meiosis I
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Prophase I
Metaphase I
Anaphase I
Telophase I
End products
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B.
C.
D.
E.
V.
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Meiosis II
A.
B.
C.
D.
E.
Prophase II
Metaphase II
Anaphase II
Telophase II
Final products
VI.
Comparison between mitosis and meiosis
Event
Synapsis occurs
Sister chromatids
separate
Homologous
chromosomes separate
Crossing over occurs
Tetrads form
Haploid cells form
Identical daughter cells
form
Mitosis
Meiosis I
Meiosis II
VII. Meiosis and simple inheritance
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A. Sex determination
1. autosomes
2. sex chromosomes
3. products of meiosis
4. nature of sperm
determines sex
• 5. sex ratios
B. Inheritance of somatic traits
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1. Theory of particulate inheritance
2. Each body trait is affected by two alleles
3. One inherited from father and other from mother
4. Two factors separate upon gamete formation during
meiosis
• 5. Terms of inheritance
a. dominant
b. recessive
c. genotype
d. phenotype
6. Inheritance of eye color
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a.
b.
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d.
Dominant allele produces pigment (E)
Recessive allele produces no pigment (e)
Possible genotypes
Resulting phenotypes
7. Sample problem
• In humans, freckles are dominant to no freckles. Mary,
who has no freckles, is planning on having children with
Paul. Paul, who has freckles, was born to a freckless
woman. Mary wants to know the probability of her in
utero son has of having freckles.
• How do we start?
• List the symbols to be used to represent the alleles.
• What is the mother’s phenotype? Genotype?
• What is the father’s phenotype? What does his
genotype have to be?
• What alleles are carried in the eggs and sperm of the
couple?
• Create the punnett square.
• What will be the name of the son which is not born yet?