Explain why a mutation in the viral RNA leads to a change in the 3D shape of the protein antigens (3 marks)

A mutation in the viral RNA results in a change in the RNA base sequences. This can result in a change in the amino acid sequence during translation. This then changes the position of intramolecular bonds, such as hydrogen bonds or disulphide bonds. This results in a change in the 3D structure of the protein, leading to a change in the shape of the protein antigens.