Question Video: Recalling the Definition of a Gamete | Nagwa Question Video: Recalling the Definition of a Gamete | Nagwa

Question Video: Recalling the Definition of a Gamete Science • Third Year of Preparatory School

Which of the following is a defining feature of a gamete? [A] A gamete contains double the genetic material of a normal body cell. [B] A gamete contains half the genetic material of a normal body cell. [C] A gamete is able to replicate and divide indefinitely. [D] A gamete is formed by mitosis, not meiosis.

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Video Transcript

Which of the following is a defining feature of a gamete? (A) A gamete contains double the genetic material of a normal body cell. (B) A gamete contains half the genetic material of a normal body cell. (C) A gamete is able to replicate and divide indefinitely. Or (D) a gamete is formed by mitosis, not meiosis.

This question asks us about gametes, otherwise known as sex cells, which are very important for the process of sexual reproduction. Can you remember how sex cells are formed? They are produced through a process called meiosis. Most cells in the human body are called somatic cells, and they make up every organ and tissue apart from the sex cells contained in the gonads. Human somatic cells tend to contain 46 chromosomes. They are called diploid cells because they have a full set of genetic material having received DNA from both a biological mother and biological father.

These two sets of DNA are provided by the gametes, which are haploid cells as they contain half the number of chromosomes of typical somatic cells, which in humans is only 23 chromosomes as opposed to 46. Gametes are called egg cells in biological females and sperm cells in biological males. Unlike gametes, which are formed through meiosis, somatic cells are produced by mitosis, which allows normal body tissues to grow by increasing their cell number. As this question focuses on the defining features of gametes, let’s take a closer look at meiosis.

The process of meiosis converts a diploid cell into four haploid cells by halving the genetic information in the original cell. Let’s take a look at an example of a diploid cell with six chromosomes, three that came from the biological mother and three that came from the biological father, arranged into homologous pairs. Before meiosis can begin, these six chromosomes are replicated. During the first phase of meiosis, the homologous pairs of chromosomes are pulled apart into separate cells, halving the number of chromosomes in each cell compared to the original diploid cell.

The cells will then undergo a second division during meiosis, which pulls apart each replicated chromosome to produce four haploid gametes, which in this example will each contain only three chromosomes. In other words, each gamete contains half the genetic material of the original diploid body cell. We now have enough information to answer our question. The defining feature of a gamete is (B). A gamete contains half the genetic material of a normal body cell.

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