MeiosisA prelude to reproduction I Terminology A karyotype

I. Terminology • A. karyotype – 1. human 46 chromosomes – 2. homologous pairs

B. Chromatin • 1. 1. 8 meters • 2. DNA • 3. exists in

C. Relationship between chromatin and chromosome • • 1. 2. 3. 4. chromatin chromosomes

D. Terms of chromosome structure • • 1. 2. 3. 4. Monad Dyad Centromere

E. Homologous chromosome pairs • • • 1. definition 2. paternal vs. maternal 3.

How many chromosomes do you see? 1. 2. 3. 4. 4 8 10 No

II. Review of mitosis • • • A. B. C. D. E. Prophase Metaphase

III. Meiosis overview • A. Importance? • B. Two separate divisions – Meiosis I

IV. Meiosis I • • • Prophase I Metaphase I Anaphase I Telophase I

V. • • • Meiosis II A. B. C. D. E. Prophase II Metaphase

VI. Comparison between mitosis and meiosis Event Synapsis occurs Sister chromatids separate Homologous chromosomes

VII. Meiosis and simple inheritance • • • A. Sex determination 1. autosomes 2.

B. Inheritance of somatic traits • • 1. Theory of particulate inheritance 2. Each

6. Inheritance of eye color • • a. b. c. d. Dominant allele produces

7. Sample problem • In humans, freckles are dominant to no freckles. Mary, who

Slides: 16

Download presentation

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 • • 1. 2. 3. 4. chromatin chromosomes histone proteins nucleosome

D. Terms of chromosome structure • • 1. 2. 3. 4. Monad Dyad Centromere Sister chromatids

E. Homologous chromosome pairs • • • 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. . .

II. Review of mitosis • • • A. B. C. 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 • • • Prophase I Metaphase I Anaphase I Telophase I End products A. B. C. D. E.

V. • • • 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 II

VII. Meiosis and simple inheritance • • • 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 • • 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 • • a. b. c. 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, 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?