How many chromosomes does a human zygote contain compared to a human ovum?

A human zygote contains 46 chromosomes, while a human ovum, which is the female gamete, contains 23 chromosomes. During fertilization, a sperm cell, which also contains 23 chromosomes, merges with the ovum. This process combines the genetic material from both the mother and the father, resulting in a zygote that has a complete set of chromosomes—23 pairs, for a total of 46.

In humans, each pair consists of one chromosome from the mother and one from the father, thus restoring the diploid state that is characteristic of zygotes. The zygote represents the first stage of development following fertilization, incorporating genetic material from both parents, while the ovum, being a haploid cell, has half the number of chromosomes necessary to form the complete set for a new organism.