Flashcards · Biology · Reproduction, Meiosis and Variation
Meiosis and Gametes
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What is a gamete?
A sex cell, such as a sperm or an egg, with half the normal number of chromosomes.
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How many chromosomes are in a human gamete?
23.
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What does haploid mean?
Having one set of chromosomes.
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What does diploid mean?
Having two sets of chromosomes, in pairs.
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Where in the body does meiosis happen?
In the reproductive organs: the ovaries and the testes.
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How many cells does meiosis make from one cell?
Four.
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Are the cells made by meiosis identical?
No. They are genetically different from each other.
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What happens at fertilisation?
A male and a female gamete fuse, to make a diploid zygote.
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How many chromosomes are in a human zygote?
46.
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Why must gametes be haploid?
So that the chromosome number is the same in every generation after fertilisation.
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Which type of division makes two identical cells?
Mitosis.
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Which type of division is used for growth and repair?
Mitosis.
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A cell has 24 chromosomes. How many are in a gamete?
12.
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Why is meiosis important in producing variation?
Chromosomes are shared out randomly, so each gamete has a different mixture of genes.
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Do you need to know the stages of meiosis?
No. You need the main events and the result.
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What is the common mistake about meiosis?
Saying it makes two cells, or that the cells are identical. It makes four different ones.