1.4 - Mutations



Higher Human Biology 1.4

Mutations are rare and random changes to DNA. 

Mutations in genes result in a change in the genetic code which results in a change in one or more amino acids. The change in amino acids change the production of proteins, either no protein or an altered protein will be synthesised.

Mutations in chromosomes affect the structure of chromosomes present in cells.

Single gene mutations involve the alteration of a DNA nucleotide sequence. There are three types of single-gene mutations:

    • substitution 
    • insertion
    • deletion

Substitution is when a single nucleotide is removed from a DNA sequence and is replaced by another with a different base

Substitution can either have a minor or major impact on the protein structure. Substitution causes missense, nonsense and splice-site

    • missense
      • one amino acid is switched for another 
      • minor impact on the protein structure
      • may result in a non-functional protein or have little effect on the protein


No comments have yet been made