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18 Ways to Make a Baby  
How Cells Divide: Mitosis vs. Meiosis
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Mitosis


Meiosis





Before We Split
Welcome to Mitosis vs. Meiosis.

This half of the screen illustrates mitosis—the division of a cell's nucleus. Along with cytokinesis (the division of the rest of a cell), mitosis results in a parent cell dividing into two daughter cells. The genetic information within each of these daughter cells is identical.

A human cell contains 46 chromosomes. To simplify our illustration, we'll show only four.


Before We Split
Though the genetic code of a human being is contained within 46 chromosomes, only half of this number exists within the cell of a sperm or egg. If the cells didn't have half, a fertilized egg would contain 92 chromosomes and be untenable. Meiosis, a type of cell division specific to reproduction, avoids this by halving the number of chromosomes in a cell.

The cell shown here will divide twice, resulting in four cells. Each of these cells will have only half the number of chromosomes, but each chromosome will contain genetic information from both parents.



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