Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half...
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Transcript of Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half...
![Page 1: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/1.jpg)
MeiosisCell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes. This produces the gametes.
![Page 2: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/2.jpg)
Why Meiosis?• Meiosis • To produce gametes (sex) cells• Egg and Sperm cells
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Terms Review…
• Haploid: (n) having a single set of chromosomes in the cell. ex. Gametes; humans have 23 chromosomes in sex cells (egg and sperm cells)
• Diploid: (2n) having two sets of homologous chromosome in the cell. ex. Somatic (body) cells; humans have 23 pairs or 46 chromosomes in body cells
Human Karyotype with 23 pairs of homologous chromosomes for a diploid number of 46; 2n = 2(23) = 46
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Terms Continued
• Homologous chromosomes – two sets of chromosome in a pair, with one set coming from a male parent and the other set coming from the female parent.
• Tetrad – pairing of homologous chromosomes during meiosis I, and such pairing has 4 (tetra) chromatids. These chromatids can then exchange genetic material.
• Crossing-over – process in which tetrad of homologous chromosomes exchange portions of their chromatids, and thus genetic material is exchanged; this occurs during Prophase I of meiosis.
• Gametes – sex cells; involved in sexual reproduction. Male gametes are called sperm cells and female gametes are called egg cells; sperm are produced in testes and egg are produced in ovaries by meiosis.
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![Page 6: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/6.jpg)
Section 11-4
Crossing-Over
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Section 11-4
Crossing-Over
![Page 8: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/8.jpg)
Section 11-4
Crossing-Over
![Page 9: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/9.jpg)
Crossing Over
• What is happening?Exchange of genetic material between homologous chromosomes
• How does this affect the individual (offspring)? Creates genetic variation
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Crossing Over
![Page 11: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/11.jpg)
How does Meiosis Occur?
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Meiosis Review
1. Is the beginning parent cell diploid or haploid (2n or n)?
2. Are the resulting daughter cells diploid or haploid (2n or n)?
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More Meiosis Review
3. How many daughter cells are produced?
4.Are the resulting daughter cells different
from the parent cell?
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More Meiosis Review
5. Are the resulting daughter cells different from each other?
7. How many chromosomes are in a human daughter cell?
6. How many chromosomes are in a human parent cell?
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More Meiosis Review
8. What types of cells are produced by meiosis?
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Fertilization
New Individual46
Mom
23
Dad
23
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This is how new organisms are made!!
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Let’s reviewMitosis & Meiosis
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![Page 20: Meiosis Cell division process whereby the number of chromosomes in a diploid cell is reduced by half through the separation of homologous chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062722/56649f275503460f94c3f09c/html5/thumbnails/20.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
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Mitosis vs. Meiosis
Event Mitosis Meiosis
Beginning cells diploid (2n)
Beginning cells haploid (n)
Ending cells diploid (2n)
Ending cells haploid (n)
Produces egg and sperm
Produces body cells
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