The gamete containing the genes contributed by the mother is called an ovum or an egg cell. Fertilization occurs when the ovum fuses with the male gamete, called a sperm cell.Continue Reading
Gametes are formed by a special kind of cell division called meiosis. Unlike mitotic cell division, meiotic division results in daughter cells with only half the normal number of chromosomes. The combination of two of these haploid gametes, a sperm and an egg, results in a zygote with a full set of chromosomes.
While a human male produces sperm cells continuously from the time of puberty, a human female is born with a complete set of egg cells. At puberty, these egg cells begin to mature and are released one by one monthly until the onset of menopause. During a woman's lifetime, an average of 300 to 400 egg cells mature and become viable. Upon maturation, the egg cell descends into one of the fallopian tubes, a process called ovulation. If an egg cell isn't fertilized, it's sloughed off during menstruation.
The egg cells of many animal species contain a yolk, which nourishes the developing embryo until the egg hatches. While human egg cells contain a small nutritive yolk, it's only enough to nurture the zygote through the earliest stages of development. After implantation in the uterine wall, the embryo receives oxygen and nutrients from the mother's body for the duration of the pregnancy.Learn more about Molecular Biology & DNA