1.6 - Mutations Flashcards
What is a mutation?
A random change in the DNA that can result in no protein or an altered protein being synthesised.
Name the three types of single gene mutations?
Substitution, Insertion, Deletion
Name the four types of chromosomes mutations?
Translocation, Inversion, Deletion, Duplication
What happens in a substitution mutation?
One base is replaced by another
What happens during deletion point mutations?
One base is removed
What happens during insertion point mutations?
One base is added
What is meant by a missense mutation?
When one amino acid has been substituted and this results in a non-functional protein or may have little effect on the protein.
What is meant by a nonsense mutation?
When a premature stop codon has been inserted and results in a shorter protein.
What is the result of a splice-site mutation?
In some introns being retained in the mature mRNA and/or some exons not being included in the mature transcript.
Which mutations are frameshift mutations?
Insertion and deletion
What is meant by a frameshift mutation?
Causes all of the codons and all of the amino acids after the mutation to be changed. This has a major effect on the protein produced.
What is meant by a chromosome mutation?
A change to the sequence of genes on a chromosome.
What happens in a translocation mutation?
A section of a chromosome is added to another chromosome, not it’s homologous partner.
What happens in an inversion mutation?
Where a section of a chromosome is reversed.
What happens in a deletion chromosome mutation?
A section of a chromosome is removed.
What happens in a duplication mutation?
A section of a chromosome is added from it’s homologous partner.
What is a mutagenic agent?
Something which increases the frequency of mutations.
Give an example of a mutagenic agent?
Mustard gas, U.V. Radiation, X-Rays
Why is duplication important in evolution?
duplication allows potential beneficial mutations to occur in a duplicated gene whilst the original gene can still be expressed to produce its protein.
Which type of point mutation can lead to an expansion of a nucleotide sequence?
Insertion
Explain how a mutation can lead to the same amino acid being produced?
Many amino acids have more than one codon.
