IGCSE Biology glossary
Fertilisation
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
The fusion of the nucleus of a male gamete (sperm) with the nucleus of a female gamete (egg cell) to form a zygote. In humans, fertilisation usually occurs in the oviduct (fallopian tube). The zygote is diploid, having received one set of chromosomes from each parent.
What to include in an exam answer
Say 'fusion of nuclei' not 'fusion of cells'. This is a key marking point. In plants, fertilisation occurs when the pollen tube nucleus fuses with the egg cell nucleus in the ovule.
Example in context
Define fertilisation (2 marks): The fusion of the nucleus of a male gamete with the nucleus of a female gamete to form a zygote.
Related syllabus topic
Reproduction