IGCSE Biology glossary
Haploid
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Definition
A cell that has one complete set of chromosomes, half the diploid number. In humans, haploid cells (gametes) contain 23 chromosomes. Haploid cells are produced by meiosis and restore the diploid number when they fuse at fertilisation.
What to include in an exam answer
Haploid is written as n. In humans, n = 23. Only gametes are haploid. Meiosis is the type of cell division that produces haploid cells from diploid cells.
Example in context
Explain why meiosis is necessary for sexual reproduction (2 marks): Meiosis produces haploid gametes with half the chromosome number. When two haploid gametes fuse at fertilisation, the diploid number is restored, maintaining a constant chromosome number across generations.
Related syllabus topic
Inheritance