Reproduction and meiosis — Edexcel GCSE Combined Science
How meiosis makes four genetically different gametes with half the number of chromosomes, and how fertilisation restores the full number.
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Meiosis is the type of cell division that makes gametes. One parent cell divides to produce four daughter cells, each with half the number of chromosomes, which are genetically different from each other and from the parent cell. In humans, meiosis makes sperm and egg cells with 23 chromosomes, and fertilisation restores the full 46.
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Quick check questions
Give one advantage and one disadvantage of asexual reproduction.
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Advantage: no need to find a mate (or rapid reproductive cycle). Disadvantage: no variation in the population.
Give one advantage and one disadvantage of sexual reproduction.
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Advantage: variation in the population. Disadvantage: the requirement to find a mate.
How many daughter cells does one meiotic division produce?
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Four.
How many chromosomes are in a human gamete?
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23, which is half the number in a body cell (46).
Frequently asked questions
Why is meiosis important for sexual reproduction?
Meiosis is important because it makes gametes with half the number of chromosomes of a body cell. In humans, sperm and egg cells have 23 chromosomes, so when they fuse at fertilisation the zygote has the full 46. The gametes are also genetically different, which produces variation in the offspring.
What is the difference between mitosis and meiosis?
Mitosis produces genetically identical diploid body cells. Meiosis produces four genetically different haploid gametes, each with half the number of chromosomes of the parent cell. In humans, body cells made by mitosis have 46 chromosomes, while the sperm and egg cells made by meiosis have 23, so fertilisation restores 46.
Written and checked against the Edexcel GCSE Combined Science (1SC0) specification · Updated October 2026