3.25 understand that division of a cell by meiosis produces four cells, each with half the numberof chromosomes, and that this results in the formation of genetially different haploid cells

Gametes (sex cells) are produced by meiosis. Meiosis is when a cell reproduces by splitting itseld to form four haploid cells whose chromosomes are not identical. This is the process...


1- The cell duplicates its DNA (chromosomes) so there is enough DNA for each new cell

2- The chromosomes line up in pairs in the centre of the cell

3- The pairs cross over, some of the DNA from each chromosome is swapped. This means each new cell will have a mixture of the two original chromosomes.

4- The chromosomes are pulled apart and they form 2 separate cells

5- These cells are pulled apart, the arms of the chromosomes are pulled apart too (so there is one arm in each cell).

This results in four haploid gametes (haploid because they have half the number, only 23, of chromosomes rather than 46 as each cell has one arm of a chromosome). this means all four gametes are genetically different.

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