Meiosis Remember Mitosis Before a cell divides the
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Meiosis
![Remember Mitosis? • Before a cell divides, the number of chromosomes (the DNA) must Remember Mitosis? • Before a cell divides, the number of chromosomes (the DNA) must](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-2.jpg)
Remember Mitosis? • Before a cell divides, the number of chromosomes (the DNA) must double. • Then each new cell can receive the correct number of chromosomes (DNA).
![MITOSIS • Mitosis is when the nucleus of the cell divides. one nucleus one MITOSIS • Mitosis is when the nucleus of the cell divides. one nucleus one](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-3.jpg)
MITOSIS • Mitosis is when the nucleus of the cell divides. one nucleus one cell identical nuclei identical DNA two nuclei two cells
![MITOSIS Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate MITOSIS Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-4.jpg)
MITOSIS Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate Two daughter cells
![Mitosis Mitosis](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-5.jpg)
Mitosis
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Mitosis
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Mitosis
![It’s all about chromosomes! • There are 46 chromosomes in human body cells • It’s all about chromosomes! • There are 46 chromosomes in human body cells •](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-8.jpg)
It’s all about chromosomes! • There are 46 chromosomes in human body cells • The number of chromosomes remain constant during Mitosis 46 46 46
![What is Meiosis? • Meiosis is the formation of gametes (egg or sperm) with What is Meiosis? • Meiosis is the formation of gametes (egg or sperm) with](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-9.jpg)
What is Meiosis? • Meiosis is the formation of gametes (egg or sperm) with a haploid chromosome number, Fertilized Egg Cell
![What is Meiosis? • The fertilized egg (zygote) produced by the sperm uniting with What is Meiosis? • The fertilized egg (zygote) produced by the sperm uniting with](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-10.jpg)
What is Meiosis? • The fertilized egg (zygote) produced by the sperm uniting with the egg then undergoes mitotic division to make the baby. Fertilized Egg Cell
![Why Meiosis? • The gametes must have only half the necessary chromosome number for Why Meiosis? • The gametes must have only half the necessary chromosome number for](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-11.jpg)
Why Meiosis? • The gametes must have only half the necessary chromosome number for a species 23 • When two gametes unite, the resulting cell must have the exact chromosome number for that species. 23 46
![Cell Differentiation Nerve Cells Muscle Cells Blood Cells Skin Cells Stem Cells • New Cell Differentiation Nerve Cells Muscle Cells Blood Cells Skin Cells Stem Cells • New](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-12.jpg)
Cell Differentiation Nerve Cells Muscle Cells Blood Cells Skin Cells Stem Cells • New individuals arise from zygote stem cells through cellular differentiation
![Meiosis: In a nut shell…. • 4 daughter cells produced • Each daughter cell Meiosis: In a nut shell…. • 4 daughter cells produced • Each daughter cell](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-13.jpg)
Meiosis: In a nut shell…. • 4 daughter cells produced • Each daughter cell has half the chromosomes of the parent • 2 sets of cell division involved
![Meiosis • Meiosis begins with a diploid parent cell • Meiosis ends with four Meiosis • Meiosis begins with a diploid parent cell • Meiosis ends with four](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-14.jpg)
Meiosis • Meiosis begins with a diploid parent cell • Meiosis ends with four haploid daughter cells
![MEIOSIS Paternal Homologs • Meiosis has two divisions • Division 1, immediately followed by MEIOSIS Paternal Homologs • Meiosis has two divisions • Division 1, immediately followed by](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-15.jpg)
MEIOSIS Paternal Homologs • Meiosis has two divisions • Division 1, immediately followed by Division II Two Daughter Cells 2 nd Division of Mieosis 1 st Division of Meiosis Maternal Homologs Four Daughter Cells
![Meiosis Meiosis](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-16.jpg)
Meiosis
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Meiosis
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Meiosis
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Meiosis
![Meiosis What differences can be seen with meiosis at this point? Meiosis What differences can be seen with meiosis at this point?](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-20.jpg)
Meiosis What differences can be seen with meiosis at this point?
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Meiosis
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Meiosis
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Meiosis
![Meiosis What differences can be seen with meiosis at this point? Meiosis What differences can be seen with meiosis at this point?](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-24.jpg)
Meiosis What differences can be seen with meiosis at this point?
![](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-25.jpg)
![Meiosis Diversity • Meiosis results in gamete cells unlike the parent cell. • Gamete Meiosis Diversity • Meiosis results in gamete cells unlike the parent cell. • Gamete](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-26.jpg)
Meiosis Diversity • Meiosis results in gamete cells unlike the parent cell. • Gamete cells have only half the chromosome number. • Each of the four gamete haploid cells have a different mix of chromosomes.
![Meiosis Diversity • Additional diversity can occur because of crossing over. • Crossing causes Meiosis Diversity • Additional diversity can occur because of crossing over. • Crossing causes](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-27.jpg)
Meiosis Diversity • Additional diversity can occur because of crossing over. • Crossing causes parts of one chromosome to trade with another like chromosome. . • Certain traits “remix”.
![Crossing Over • What is happening? a A b B c C a a Crossing Over • What is happening? a A b B c C a a](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-28.jpg)
Crossing Over • What is happening? a A b B c C a a A A b b B B c c C C a a A A b b B B c C c C • How does this affect the individual (offspring)? a b A B c C
![Crossing Over • Click the link for a crossing over animation. • http: //www. Crossing Over • Click the link for a crossing over animation. • http: //www.](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-29.jpg)
Crossing Over • Click the link for a crossing over animation. • http: //www. tokyomed. ac. jp/genet/anm/mimov. gif
![MEIOSIS – 6. Drawing • Meiosis has two divisions. • Meiosis results in four MEIOSIS – 6. Drawing • Meiosis has two divisions. • Meiosis results in four](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-30.jpg)
MEIOSIS – 6. Drawing • Meiosis has two divisions. • Meiosis results in four haploid cells unlike the parent cell.
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![Mitosis vs. Meiosis Event Mitosis Meiosis Produces 4 cells Produces 2 cells New cells Mitosis vs. Meiosis Event Mitosis Meiosis Produces 4 cells Produces 2 cells New cells](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-32.jpg)
Mitosis vs. Meiosis Event Mitosis Meiosis Produces 4 cells Produces 2 cells New cells identical New cells different New cells have the same number of chromosomes as parent New cells have fewer chromosomes than parent √ √ √
![Mitosis vs. Meiosis Event Beginning cells diploid (2 n) Mitosis √ Meiosis √ Beginning Mitosis vs. Meiosis Event Beginning cells diploid (2 n) Mitosis √ Meiosis √ Beginning](http://slidetodoc.com/presentation_image/4c9e4c19ddb691e5d4fc27e86bfc422b/image-33.jpg)
Mitosis vs. Meiosis Event Beginning cells diploid (2 n) Mitosis √ Meiosis √ Beginning cells haploid (n) Ending cells diploid (2 n) √ √ √ Ending cells haploid (n) Produces egg and sperm Produces body cells √
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