DNA mutations

• Mutation is a change in the DNA base sequence
• Mutations happen spontaneously in our cells, particularly during DNA duplication before cell division
• Carcinogens and certain types of radiation increase the risk of mutations
• A gene is a section of DNA that codes for a protein
• Each group of 3 bases in DNA is called a triplet or a codon and codes for one of the 20 different amino acids
• A mutation in DNA can change the amino acid that a codon codes for, leading to different proteins being formed
• Mutations can have knock-on effects by changing the shape or function of proteins, such as enzymes
• Most mutations only affect proteins slightly, so they still work in basically the same way
• Most mutations occur in non-coding DNA, which doesn't code for proteins
• Non-coding DNA plays a role in gene expression, determining whether genes are turned on or off
• There are three types of mutations: substitutions, insertions, and deletions
• Substitution mutation: one base is changed for another, altering the amino acid sequence
• Insertion mutation: an extra base is inserted, shifting all subsequent bases and changing the amino acid chain
• Deletion mutation: one base is deleted, shifting all subsequent bases and changing the amino acid chain