What is a DNA molecule?

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A DNA molecule is made up of two chains or strands wound around each other in a spiral known as a double helix.

Each strand consists of a chain of sugar (deoxyribose) molecules, each attached to a phosphate group and one of four smaller molecules called organic bases.

What are the organic bases?

The organic bases sit like pearls on a string in a specific order. The strings are the strands of sugar molecules that make up the double helix. Together the bases form a code not dissimilar to the dots, dashes and spaces that make up Morse code. The four organic bases are called:

• Adenine (A)
• Guanine (G)
• Cytosine (C)
• Thymine (T)

The two strands of DNA are twisted in such a way that the bases sit opposite each other in a special pattern. An A on one strand will always be opposite a T on the other strand, and a G on one strand will always sit opposite a C on the other.