IGCSE Biology Human Reproduction Practice Test 2026 – Complete All-in-One Study Guide for Exam Success!

A human gamete, which can be either a sperm or an egg, contains 23 chromosomes. This is half the number of chromosomes found in somatic (body) cells, which contain 46 chromosomes in total. The gametes are produced through a type of cell division known meiosis, which reduces the chromosome number by half to ensure that when a sperm and egg combine during fertilization, the resulting zygote has the correct diploid number of 46 chromosomes. This reduction is essential for maintaining the stability of the species' chromosome number across generations. Each gamete carries one set of chromosomes, which contributes to genetic diversity in offspring upon fertilization.