Top Banner
Chapter 13 Meiosis
37

Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

May 14, 2018

Download

Documents

leminh@
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Chapter 13 Meiosis

Page 2: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Chapter 13 Meiosis

• Terms – Heredity

• Transmission of traits to offspring

– Variation • Genetic variation in population

– Genetics • Study of heredity

– Genes • DNA coded information for protein

– Gametes • Sperm and egg (and spores)

Page 3: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

sexual reproduction

• 2 parents give rise to genetically unique offspring

Page 4: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Sexual Life Cycles

• Life cycle – from conception to production of offspring

Page 5: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Some organisms can also reproduce asexually

Page 6: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Other animals and plants reproduce sexually

Male sea star releasing sperm into water, some sea stars are hermaphrodites and release both sperm and egg

Page 7: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some
Page 8: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Example: humans

• Somatic cells (body cells)

– 46 chromosomes

– 23 pairs 2n (diploid) = 46

Page 9: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Human chromosomes

Page 10: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Arranged in homologous pairs

Autosomes = pairs 1 – 22 Sex chromosomes = pair 23 XX = female XY = male

Page 11: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Germ line cells (gametes)– ovary/testes

– 1n (haploid) = 23

Fertilization 1n + 1n = 2n

Ex. Fruit fly egg has 4 chromosomes (1n). How many chromosomes in a sperm? A fly larval cell? An adult somatic cell?

Page 12: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Sperm + egg--- zygote fertilization

Haploid diploid haploid diploid etc………….

Page 13: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Humans: 2n = n = what makes chromosomes homologous?

Homologous chromosomes

Same length Same genes at same locations

Page 14: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

When meiosis is complete:

4 new haploid cells

genetically unique

Page 15: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Interphase

• Same as in mitosis

• Chromosomes replicate

• Centrioles replicate

Sister chromatids identical

Page 16: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some
Page 17: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Stages of Meiosis

• Prophase I

1. Nuclear envelope breaks down

2. Chromosomes (sister chromatids) condense

The diploid number of this cell is ? The number of pairs of homologous chromosomes is?

Page 18: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

3. Centrioles to poles

4. Spindle forms

Page 19: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Mitotic spindle

– directs the movement of chromosomes

Describe the anatomy of the mitotic spindle

Page 20: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Prophase I

5. Synapsis

replicated homologous chromosomes line up to form a tetrad

What is happening here??

Page 21: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Which is prophase of mitosis? Prophase I of meiosis?

Page 22: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

6. Crossing over

• Non -sister chromatids exchange

• Creates diversity!

Page 23: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Prophase I • Crossing over – note chiasmata

How many sister chromatids participate in each tetrad?

What is this structure?

Page 24: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Chiasma – the X observed

after crossing over

Page 25: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Metaphase I

– Tetrads line up along metaphase plate

Page 26: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Which is metaphase of mitosis?

Metaphase I of meiosis?

Page 27: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Anaphase I

Homologs separate and move towards opposite poles

Note: sister chromatids connected

Page 28: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Telophase I

– Nuclear membranes form around chromosomes

cytokinesis • Division of cytoplasm

2 haploid daughter cells

Page 29: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Overview of Meiosis 1

• Bioflix meiosis animation

• Meiosis I is =reduction division

Each cell has 1 set of chromosomes

(replicated and recombined)

Page 30: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Meiosis II

• Prophase II

Page 31: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Metaphase II

Page 32: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• Anaphase II

Page 33: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Telophase II

4 genetically unique haploid cells

Page 34: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Meiosis and genetic variation 1. crossing over (prophase I) recombinant

chromosomes

2. independent assortment

random orientation of homologous chromosomes are metaphase I

Page 35: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

• 3. random fertilization

Humans:

223 X 223 =

Page 36: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Compare mitosis and meiosis

Page 37: Chapter 13 Meiosis - MCCC - West Windsor, NJblinderl/documents/Chapter13Meiosispost.pdf•Other animals and plants reproduce sexually Male sea star releasing sperm into water, some

Overview of Meiosis