What Are Gametes?

Gametes

Gametes are reproductive cells. In animals, the male gametes are sperms and female gamete is the ovum or egg cells. These are typically haploid cells which fuse forming diploid entities.

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Gametes Definition

Also referred to as sex cells, gametes are reproductive cells of an entity. These are haploid cells wherein each of it carries one copy of chromosome. Male gametes are known as sperms while female gametes are known as ova or eggs. The reproductive cells are an outcome of the process of meiosis.

During this type of cell division, the diploid parent cell having two copies of each chromosome experiences one round of DNA replication followed by two distinct cycles of nuclear division to generate four diploid cells. In turn, these cells go on to form the ova or the sperm.

Sperms are developed in the testes of males while the ova matures in the ovaries of females. Each of the spermatozoan or the sperm cell is motile and small. It has a flagellum enabling the cell to move and propel. The ovum or the egg cell on the other side is comparatively large and non-motile. During fertilization, these haploid cells fuse forming diploid entities.

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.

Also Explore: MCQs on Sex Determination for NEET

Formation of Gametes

Meiosis, a two-step process gives rise to gametes. The outcome of this process is 4 haploid daughter cells, each of which contains only one set of chromosomes. Through the process of fertilization (which can either be external or internal), they unite forming the zygote. The zygote is the future foetus which is diploid in nature containing two sets of chromosomes, each from both the parents.

Modes of Sexual Reproduction

The shape and size of gametes largely decide the mode of sexual reproduction. While some male and female gametes are almost of the same size, some others vary by a large margin. In a few species of fungi and algae, both male and female gametes are almost of the same size and are motile. When two similar gametes unite, it is isogamy. While the formation of gametes having dissimilar shapes and sizes is known as heterogamy or anisogamy. There is a particular form of anisogamy called oogamy observed in higher species of animals and plants (also in some fungi and algae). In this, the female gamete is much larger and is non-motile compared to its male counterpart. This is the reproduction observed in humans.

Gametes and Chromosomes

The gametes in humans are haploid cells which comprise 23 pairs of chromosomes. Haploid cell are cells containing one set of chromosomes. The haploid condition can refer to the chromosomal number in sperm or egg cells having a single set of chromosomes. Number of chromosomes in one set is indicated as “n” which is also referred to as haploid number. n is 23 in humans.

Gametes have half the chromosomes present in normal diploid cells of the body which are called somatic cells. It is during the process of meiosis, wherein chromosomes are reduced in a parent diploid cell by half, that haploid gametes are produced.

This was a brief on gametes. Visit us at BYJU’S NEET for more related content.

Frequently Asked Questions

Q1

What do you mean by gametes?

Gametes or sex cells are reproductive cells. These are haploid cells wherein each of them carries one copy of the chromosome. Usually, a mature haploid male and female gamete fuse to form a zygote in sexual reproduction.

Q2

What are male and female gametes?

Sperms and Ova are the male and female gametes respectively. Sperms are developed in the testes of males while the ova matures in the ovaries of females. Also, the female gametes are larger than the male gametes.

Q3

What is sex determination?

It determines the sexual characteristics in an organism. The XY sex-determination system is used to classify sexes in some insects, snakes, fish, plants and many mammals including humans. This system determines the sex using a pair of chromosomes. The zygote with XY chromosomes develop into a male and the ones with XX develops into a female.

Q4

What is the role of gametes in reproduction?

The main role of gametes in reproduction is to conduct fertilization in entities that can sexually reproduce. It is during the event of fertilization that the male gametes (sperm) unites with the female gametes (egg).

Also Check:

Human Reproduction
Reproduction In Organisms

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