Gene mutations Flashcards
What is a mutation?
Any change to the quantity or base sequence of the DNA of an organism.
What is a gene mutation?
Any change to the nucleotide bases or the sequence of bases.
What are chromosome mutations?
Changes to the quality of DNA
What is a substitution mutation?
When a nucleotide is replaced by another nucleotide that has a different base.
What does degenerate mean?
When more than 1 codons can code for an amino acid.
What can substitution mutations result in?
- The mRNA codes for a different amino acid in the polypeptide chain -> may reduce function or have no function
- Could code for a stop codon -> rustler in truncated protein. Can reduce or remove function
What is a deletion mutation?
When a nucleotide is lost from the DNA sequence
What do deletion mutations cause?
A shift in the reading frame which can change all amino acids in the polypeptide.
What is non-overlapping?
Each base in the sequence is part of only one triplet.
What does universal mean?
The same triplets code for the same amino acids in all organisms.
What are addition mutations?
Where one or more bases are added to the DNA sequence.
What can cause mutations?
They can occur spontaneously as the result of errors in DNA replication.
Mutagenic agents can increase the rate of mutations by causing damage to the DNA.
What are examples of mutagenic agents?
- Ionising radiation
- Chemicals
- Viruses
- Smoking
- UV radiation
