Base pairs: binding to a fixed partner

The double helix is the world famous form of DNA. The two strands are made up of  nucleotides. These are all loose links that are attached to each other and form a long chain.

What does a nucleotide consist of?

Each nucleotide of a DNA strand contains one of four bases:

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

Base pair: important properties of hereditary material

A base in one DNA chain is attached to a complementary base in the other chain. These bases form a so-called  base pair  according to a fixed pattern: Adenine pairs with Thymine and Guanine pairs with Cytosine. As a result, the two strands are always a mirrored copy of each other. The strands can therefore be separated and reassembled like a kind of zipper.

Three billion base pairs

The specific order of the bases in the DNA strand is the genetic code. This is a complete set of the human’s 46 chromosomes and is called the genome. The genome contains a total of about 3 billion base pairs.