Question Video: Determining the Number of Chromosomes in a Cell Nucleus after Fertilization | Nagwa Question Video: Determining the Number of Chromosomes in a Cell Nucleus after Fertilization | Nagwa

Question Video: Determining the Number of Chromosomes in a Cell Nucleus after Fertilization Science • Third Year of Preparatory School

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The diagram shows a basic outline of the process of fertilization. After fertilization, a zygote forms. The zygote shown in the diagram has 4 cells. How many chromosomes will be in the nucleus of each of these cells?

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Video Transcript

The diagram shows a basic outline of the process of fertilization. After fertilization, a zygote forms. The zygote shown in the diagram has four cells. How many chromosomes will be in the nucleus of each of these cells?

Humans reproduce by sexual reproduction. During this process, a biological female and a biological male both produce sex cells, which are also known as gametes. The female gamete is called an egg cell or ovum, and the male gamete is called a sperm cell. These gametes each contain 23 chromosomes in their nuclei, which is half the number of a regular body cell.

Next, one egg cell and one sperm cell join together in a process called fertilization. During fertilization, the nucleus of the sperm cell combines with the nucleus of the egg cell. This produces a new cell called a zygote. Because the zygote has both sets of chromosomes from the two gametes in its nucleus, it has 46 chromosomes altogether.

Once the zygote has formed, it undergoes cell division so that it can grow. It’s this process of cell division that causes the ball of four cells that you see here to eventually develop into a human baby. Every time a cell divides in this way, it produces genetically identical daughter cells, which therefore also have 46 chromosomes in their nuclei. We have therefore determined that the nucleus of each cell of the zygote will contain 46 chromosomes.

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