Download Review: difference between sexual and asexual reproduction types

Review:
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difference between sexual and asexual reproduction
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types of asexual reproduction
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advantages/disadvantages of asexual reproduction
Jan 7­3:06 PM
REMEMBER: Mitosis
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M:
A:
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What is mitosis used for?
How do the new cells compare to the old cells?
What about the production of sex cells?
Jan 7­3:09 PM
1
Meiosis:
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mitosis is used to create cells that perform a basic function: (Ex. blood cells)
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mitosis results in identical new cells because these cells will always perform the same function
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meiosis is used to produce only sex cells such as an egg or sperm
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meiosis is used be produce new cells that are somewhat different because in sex cells variety is important because it ensures genetic diversity in offspring (increases chances of their survival)
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there are 8 steps to meiosis
Jan 7­3:11 PM
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mitosis produces new cells with a full number of chromosomes (Ex. 46 in a new blood cell)
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a cell with a full number of chromosomes is called a diploid cell
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meiosis produces new cells with half the number of chromosomes (Ex. 23 in a sperm cell)
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a cell with half the number of chromosomes is called a haploid cell
Jan 7­3:15 PM
2
HAPLOID
DIPLOID
Jan 7­3:18 PM
Meiosis:
(a) Prophase I
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the genetic material has already doubled before this step (Ex. humans 46 ­ 92)
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chromosomes form into homologous pairs
Jan 7­3:23 PM
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(b) Metaphase I:
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homologous pairs move towards the equator
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this time they line up in pairs along the equator
Jan 7­3:25 PM
(c) Anaphase I:
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pairs of chromosomes are pulled toward opposite equators
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they do not separate chromosome pairs
Jan 7­3:27 PM
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(d) Telophase I:
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cytokinesis occurs and two new cells are formed each containing an equal number of chromosomes (Ex. humans have 46)
Jan 7­3:29 PM
(e) Prophase II
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homologous pairs begin to move toward the equator of the cells
Jan 7­3:30 PM
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(f) Metaphase II:
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pairs line up along the equator of the cell
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they are now preparing to split
Jan 7­3:32 PM
(h) Anaphase II:
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chromosomes now begin to be pulled apart toward the opposite poles of the cells
Jan 7­3:33 PM
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(i) Telophase II:
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the cell now split into two separate cell each with half the number of original chromosomes
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in humans these new cells are called sperm and egg each with 23 chromosomes
Jan 7­3:36 PM
Comparing Mitosis and Meiosis:
Mitosis:
Meiosis:
In body cells
In sex organs to produce sex cells
Two daughter cells
Four daughter cells
Same number of chromosomes as parent cell
One half the number of chromosomes as parent cell
Asexual reproduction
Sexual reproduction
Jan 10­11:08 AM
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Readings:
Pages 170 ­ 175
Videos:
Mitosis:
Meiosis:
Questions:
Page 179: #'s 10,11,14,16,18,21
Jan 8­7:58 AM
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