OCR A Biology
Mutation Aa Codon Gene Sequence Affects Frame Protein
A gene mutation, an alteration in DNA base sequence, can change protein synthesis. Substitutions, deletions, or insertions can alter codons, leading to missense mutations with variable effects depending on the amino acid change.
A gene mutation is an alteration in the DNA base sequence that can affect protein synthesis. Mutations like substitution, deletion, or insertion can change codons, leading to missense mutations (altered amino acids) that may have minor or significant effects depending on the amino acid's role.
| Front |
What is a gene mutation and what are the different types? |
| Back |
- mutation is alteration of DNA base sequence that affects protein synthesis if occurs in gene
- caused by substitution, deletion or insertion of nucleotides within a gene
- Substitution
- single nucleotide sub changes codon in which it occurs, now diff codon can code for diff/same AA (due to degenerate code)
- e.g missense mutations - incorperation of incorrect AA into PS, result depends on role of AA in structure of protein, conservative mutation occurs when AA change leads to AA that codes for similar properties and effect less severe, non-conservative mutation is where AA coded for different to original, so effects protein structure
- point mutation as it only affects 1 codon
- Insertion and Deletion
- added/deleted nucleotide shifts the reading frame of the sequence of bases, so changes every codon after mutation point, unless the no. of nucleotides changed is multiple of 3 (reading frame not changed, but new AA added or original deleted)
- frame shift mutation as it affects whole sequence after mutation
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OCR A Biology