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.
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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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