Meiosis (not be confused with mitosis)
What: Formation of GAMETES. In this situation the parent cell has 46 chromosomes (diploid) and will eventually make 4 daughter cells with 23 chromosomes (haploid).
Where : sex cells
Meiosis has two stages, Meiosis 1 and Meiosis 2
The first stage of Meiosis is DIFFERENT from Mitosis.
Prophase 1
Chromosomes shorten and thicken
centrioles move to opposite poles
Metaphase 1
Homologous chromosomes (one from each parent) line up
Crossing over occurs (exchange of genetic material between homologous chromosomes)
Anaphase 1
Homolous chromosomes are pulled to opposite poles of the cell
Telophase and Cytokinesis 1
Nuclear membrane forms and two daughter cells are formed (each has 23 chromosomes duplicated)
Meiosis 2 - This process looks almost identical to mitosis, the difference is the number of chromosomes. Since meiosis 1 ended with each cell containing 23 duplicate chromosomes, that is how meiosis 2 will begin.
Thursday, November 19, 2009
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