Genes Passage - How Reproduction Begins

		Cloning is an artificial way of doing what happens naturally through sexual reproduction. Therefore, to understand cloning, it helps to review what happens in sexual reproduction.

Graphic Overview of Reproduction How is an embryo formed?		When a male's sperm fertilizes a female egg, it creates a single cell in which an equal number of chromosomes from the male and the female parents are united. The fertilized egg soon divides into two connected cells. Each of these two cells carries a complete copy of the chromosomes that were in the original cell. These two cells then divide again. This process keeps repeating to form a many-celled embryo .

What dictates how a cell is structured?		After the first few rounds of divisions, cells begin to specialize . For example, some cells become nerve cells, some become skin cells , and some become blood cells. In each kind, different genes come into play. The genetic instructions that go into operation in each cell dictate the production of the particular proteins that make up the cell's structure and direct its activities .

Section	Passage	Paragraph
3	4	11

How Cloning Works	strategies \| help \| resources \| your genes \| intersect
		Passage 4 How Reproduction Begins
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