Key area 1.6 Mutations Flashcards
What are mutations?
Mutations are random changes in the genome.
What can mutations result in?
No proteins or an altered protein being synthesised.
What are the 2 types of mutation?
single gene and chromosome structure.
What is a single gene mutation?
The alteration of a single nucleotide in a DNA sequence.
What are the 3 types of single gene mutation?
Substitution, Insertion and deletion.
What happens at a Substitution mutation?
A single nucleotide is removed from a DNA sequence and replaced with another.
What happens at an Insertion mutation?
An extra nucleotide is added into the sequence.
What happens at a Deletion mutation?
A single nucleotide is removed from the sequence.
What single gene mutations result in a frameshift?
Insertion and Deletion.
What is a frameshift mutation?
When the mutation changes the entire DNA sequence after the change, resulting in different codons and different amino acids being produced.
What are the types of Substitution mutation?
Missense, nonsense and splice-site
What happens at a missense Substitution?
One codon changes resulting in a different amino acid being produced.
What happens at a non-sense Substitution?
A normal codon is changed into a stop codon. This causes the premature stop of protein synthesis and creates a polypeptide chain shorter than normal.
What happens at a splice-site Substitution?
During RNA splicing one or more introns are left in the mature transcript.
What are the types of chromosome mutations?
Deletion, Duplication, Translocation and Inversion.
