Meiosis
The cell division that makes gametes. As in mitosis the DNA is copied first, but then the cell divides twice in a row, making four cells with half the chromosomes, exactly one of each pair. A human gamete has 23 chromosomes; when two join in fertilisation the zygote has 46 again, 23 pairs with one of each from each parent, so the number stays the same generation after generation. Which chromosome of a pair goes to which gamete is a matter of chance, one reason no two offspring are alike.
Depth 1 · Foundation
You can explain why gametes need half the chromosomes, describe meiosis as two divisions making four cells with one chromosome of each pair, work out a gamete's and a zygote's chromosome numbers, and compare meiosis with mitosis.
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- 1
Foundation
You can explain why gametes need half the chromosomes, describe meiosis as two divisions making four cells with one chromosome of each pair, work out a gamete's and a zygote's chromosome numbers, and compare meiosis with mitosis.
Your path here
What's still between you and Meiosis, depth 1, in the order you can learn it.
- 1CellsDepth 1 · Foundation · The Cell
- 2Parts of a cellDepth 1 · Foundation · The Cell
- 3Parts of a cellDepth 2 · Deeper · The Cell
- 4DNADepth 1 · Foundation · Genes and Inheritance
- 5Cell divisionDepth 1 · Foundation · Genes and Inheritance
- 6Asexual reproductionDepth 1 · Foundation · Life and Its Variety
- 7Sexual reproductionDepth 1 · Foundation · Life and Its Variety
- 8GenesDepth 1 · Foundation · Genes and Inheritance
- 9MeiosisDepth 1 · Foundation · Genes and Inheritance
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