Gametes – Class 12 | Chapter – 3 | Biology Short Notes Series PDF
Gametes: Gametes are also referred commonly to as sex cells. In animals, female gametes are called ova or egg cells, and male gametes are called sperm. Ova and sperm are haploid cells, with each cell carrying only one copy of each chromosome. During fertilization, a sperm and ovum unite to form a new diploid organism.
Gametes Example
Ova and sperms are the most common gametes. These differ in size and are haploid in nature. They may experience external or internal fertilization. There are some entities, however, that produce both of these cells in the same entities. Such organisms are known as hermaphrodites. Majority of entities who reproduce sexually produce one type of gamete.
Formation of Gametes
Meiosis, a two-step process gives rise to gametes. The entire process takes place where the cells are divided through meiosis and this, in turn, produces the gametes. The entire process that consists of two steps will result in the formation of 4 different haploid daughter cells. The zygote is the future foetus which is diploid in nature containing two sets of chromosomes, each from both the parents.
Role of Gametes in the process of reproduction
Gametes are the reproductive cells used during sexual reproduction to produce a new organism called a zygote. Gametes are haploid in nature. The male gamete is called sperm with either X or Y chromosome as sex chromosome.It is much smaller than the female gamete and very mobile. It has a long tail, flagellum, that allows it to move towards the female gamete. The female gamete is called an egg or ova with X chromosome only as a sex chromosome.
Gametes are formed through meiosis (reduction division), in which a germ cell undergoes two fissions, resulting in the production of four gametes. During fertilization, male and female gametes fuse, producing a diploid (i.e., containing paired chromosomes) zygote.
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