Key learning points

1. DNA is a type of biological molecule called a nucleic acid.
2. DNA is made of two strands, each a long polymer of nucleotides, wound together in a double helix shape.
3. DNA is a polymer of four different nucleotides (A, C, G and T).
4. Each of the four types of nucleotide in DNA is made of the same sugar and a phosphate group, bonded to a different base.
5. Nucleotides in each strand of DNA pair up in a complementary way; A pairs with T, and C pairs with G.

Keywords

• DNA - DNA is a nucleic acid polymer made up of four nucleotides, it contains the genetic code in all living organisms.

• Nucleic acid - A nucleic acid is a polymer made up of nucleotides, an example is DNA.

• Polymer - A polymer is a chemical made up of smaller repeating chemical groups.

• Nucleotide - A nucleotide is a chemical group that make up the building blocks of DNA, the four types are coded A, T, C and G.

• Base - A base is the part of a nucleotide that pairs to its complementary base across the middle of the DNA double helix C-G and A-T.

Common misconception