Transcript Cell dIVISION

Mitosis and Meiosis
Asexual v. Sexual Reproduction
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“process where 1 cell splits into 2”
Replaces somatic (body) cells in multicellular
organisms
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Allows for multicelullar growth
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Allows for asexual reproduction in plants
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Chromosome – rod shaped structure made up
DNA and protein
a. held together by centromere
- holds chromatids together until they
separate during division
b. only found during cell division
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Human/animal chromosomes – sex chromosomes
and autosomes
Humans have 46 chromosomes in somatic cells
Karyotype – used to examine an individual’s
chromosomes
Haploid
Diploid
Reproductive cells (sperm and
egg)
Somatic cells (body-all other
cells)
½ the # of chromosomes (23)
Has ALL chromosomes (46)
half the DNA
Has ALL DNA
N = haploid
2N = diploid
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Haploid  Diploid = sex cell  body cell ( x by 2)
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Diploid  Haploid = body cell  sex cell ( ÷ by 2)
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Diploid  Diploid = body cell  body cell
Haploid  Haploid = sex cell  sex cell
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Dogs have 42 chromosomes in their diploid
cells. How many are in their haploid cells?
If there are 23 chromosomes in a sperm cell,
how many would be in the skin cell?
If there are 46 chromosomes in a nerve cell,
how many would be in a blood cell?
If there are 23 chromosomes in a sperm cell,
how many would be in a human ovum (egg)
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Binary Fision – two identical cells are produced from
one cell
* division in bacteria
Mitosis
Meiosis
Asexual Reproduction
Sexual Reproduction
Division of diploid cells (somatic cells)
Division of haploid cells
(reproductive cells)
Results in 2 identical daughter cells
Results in 4 haploid daughter cells
1 division
2 divisions
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“series of events leading to cell division”
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Asexual Reproduction
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Diploid cells split into 2 identical diploid cells
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Allows body cells to be replaced and cells to
GROW
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
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“sexual reproduction”
Fusing of 2 haploid gametes to form 1 diploid
zygote
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2 divisions
a. Meiosis I
b. Meiosis II
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Crossing – over
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Fertilization
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Independent Assortment