KA4 Mutations-Unit 1 Flashcards
What is a mutation?
A mutation is a change in the DNA that can result in no protein or an altered protein being synthesised.
What are the two types of mutations?
Gene Mutation
Chromosome mutation
How frequent are mutations?
They are random and rare, but their frequency can increase by mutagenic agents.
What are mutagenic agents?
Chemicals such as mustard gas.
Radiation e.g UV and X rays.
What is gene mutation?
Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of substitution, insertion or deletion of nucleotides.
How many types of substitution mutations are there?
Three- Missense, nonsense, splice site.
What is a substitution mutation?
A substitution mutation involves a change in one nucleotide in the DNA sequence of a single gene, which results in one or more codons for one or more amino acids being altered.
What is a missense mutation?
One amino acid being changed for another, which may result in a non functional protein or have little effect on the protein.
What is a nonsense mutation?
A premature stop codon being produced, resulting in a shorter protein.
What is a splice site mutation?
When some introns being retained and/or some exons not being included in the mature mRNA transcript.
What is an insertion gene mutation?
When a nucleotide is added to a DNA strand, changing the base sequence, which alters the amino acids formed.
What is deletion?
When a nucleotide is removed/ deleted from the DNA strand, resulting in alteration of the code, which changes the amino acids formed.
What effect do frame shift mutations have on a protein?
They have a major effect on the protein being produced as all the codons and all the amino acids after the mutation are changed, resulting in a non functional protein.
What is a chromosome mutation?
Chromosome structure mutations involve a change in the sequence or number of genes on a chromosome.
What are examples of chromosome mutations?
Deletion
Duplication
Inversion
Translocation
