Mutation Flashcards
What is a mutation?
A random change to the genome of an organism.
Name the three types of gene mutations?
SID
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 for another.
What is meant by a nonsense mutation?
When a premature stop codon has been inserted.
What is the result of a splice-site mutation?
An intron could remain in the mature mRNA or an exon may have been removed.
Which mutations lead to a frameshift effect?
Insertion and deletion
What is meant by a frameshift effect?
Each codon after the mutation is altered leading to the wrong amino acids being used.
What is meant by a chromosome mutation?
A change to the number or sequence of genes on a chromosome.
What happens in a translocation mutation?
A section of one chromosome becomes attached to another.
What happens in an inversion mutation?
Genes on the chromosome are flipped (or rotate 180°).
What happens in a deletion chromosome mutation?
Genes from the chromosome are deleted.
What happens in a duplication mutation?
Genes on the chromosome are repeated.
What is polyploidy?
An organism which has an extra set of chromosomes.
How does polyploidy occur?
Failure of spindle fibres to separate chromosomes during mitosis or meiosis.
How does polyploidy help drive evolution?
It provides material upon which natural selection can act.
Give two features of polyploidy plants which make them beneficial?
Increased yield, increased vigour.
Which type of point mutation can lead to an expansion of a nucleotide sequence?
Insertion
What is meant by a silent mutation?
When the mutation leads to the same amino acid being produced.
What is meant by a neutral mutation?
An amino acid with similar properties is used so the protein still functions correctly.
Explain how a mutation can lead to the same amino acid being produced?
Many amino acids have more than one codon.
What would the effect of a mutation in a regulatory sequence?
Failure in gene expression
Give an example of a mutagenic agent?
Mustard gas, U.V. Radiation, X-Rays
What is a mutagenic agent?
Something which increases the frequency of mutations.
How often do mutations occur?
Randomly, rarely, spontaneously.
