How Bases Code for a Polypeptide Chain (Edexcel International A Level Biology): Revision Note

Crick's Central Dogma

• A gene is a sequence of nucleotides that forms part of a DNA molecule (one DNA molecule contains many genes)

• This sequence of nucleotides (the gene) codes for the production of a specific polypeptide (protein)

• Protein molecules are made up of a series of amino acids bonded together

• The shape and behaviour of a protein molecule depends on the exact sequence of these amino acids (the initial sequence of amino acids is known as the primary structure of the protein molecule)

• The genes in DNA molecules, therefore, control protein structure (and as a result, protein function) as they determine the exact sequence in which the amino acids join together when proteins are synthesised in a cell

A gene is a sequence of nucleotides that codes for the production of a specific protein molecule (polypeptide)