Nucleotide

Each chain is made from four different types of monomer called nucleotides. A nucleotide contains a base; the four bases are represented by the letters A, T, C and G. Bases on one chain pair with bases on the other, helping to hold the chains together.

Each DNA strand is a long chain made from monomers called nucleotides. There are four different types of nucleotide in DNA, and they can occur in many different sequences. You do not need to recall their individual names for this specification.

The building blocks are not the same in every natural polymer: DNA is made from nucleotides, some other natural polymers are made from sugars, and proteins are made from amino acids.

DNA is made from repeating monomers called nucleotides: there are four different types of nucleotide, arranged in long chains. This does not mean that a DNA molecule contains only four nucleotides; each chain contains many of them. Two DNA chains form the familiar double helix.