Cell Repro
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Transcript of Cell Repro
Cell DivisionCell Division
By: T. Bolles, Based in Part by “Meiosis.ppt” by K. Ingemunson
MITOSIS• Chromosomes within the cell
make copies of themselves
• The cell divides into 2 cells – 1 is a clone of the other
• These are DIPLOID cells (chromosomes occur in pairs)
MITOSIS
MEIOSIS• The cell divides without
copying chromosomes
• End up with 4 cells, each of these cells has only ½ the normal number of chromosomes
• These cells are called Haploid
MEIOSIS
Meiosis I
Meiosis II
MEIOSIS
Diploid Cells• All cells in the
body except sex cells are diploid.
Haploid Cells• All cells in the
body except sex cells are diploid.
Fertilization• BODY CELL: full
number of chromosomes (two copies = diploid)
• SEX CELL: half the number of chromosomes (one copy = haploid)
• FERTILIZATION: we get genes from each of our parents
Female Sex Cell
Male Sex Cell
Why is Haploids? • If diploid cells are fertilized…
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Chromosome will keep doubling!!
2N + 2N 4N
Why is Haploids?
If haploid cells are fertilized…
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Like all cells of the body!!
N + N 2N
Sexual Reproduction• Reproductive process in which haploid
sex cells (gametes) fuse to produce a diploid fertilized egg (zygote)
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