BRAINCAKEGene Mutation
A gene mutation (point mutation) changes one or a few bases in the DNA of a gene. There are three main types.
Substitution: one base is replaced by another. Only one codon changes, so the effect depends on the new codon:
• silent: the new codon codes for the same amino acid, because the genetic code is degenerate, so there is no change to the protein
• missense: a different amino acid is coded for, which may change the protein's shape and function
• nonsense: a stop codon is formed, so a shortened, usually non-functional, polypeptide is made
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More in DNA, Genes and Protein Synthesis
- rRNA
- Protein Synthesis
- Transcription
- Translation
- Polysomes
- Mutations
- Sickle Cell Disease
- Chromosome Mutations
All 20 lessons in DNA, Genes and Protein Synthesis · All Edexcel AS-level Biology topics