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Description
Why do people look and act like people, cats look and act like cats, or frogs look and act like frogs? All of us have what is called DNA in every one of our cells. This is the genetic information we get from our parents, half from our mother, half from our father. Every time one of our cells divides, this information is passed on to the new cells to make sure the new cells look and behave like the original ones.
DNA is a molecule composed of two chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.
The two DNA strands are also known as polynucleotides as they are composed of simpler monomeric units called nucleotides.Each nucleotide is composed of one of four nitrogen-containingnucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group.
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