Unit 1- Mutations Flashcards
What is a mutation?
Mutations are changes in the DNA, either in a gene or chromosome, that can result in no protein or an altered protein being synthesised. They are rare and random. They can be useful, harmful or lethal.
What is a single gene mutation?
Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides.
What are the three single gene mutations?
Substitution, deletion, insertion.
What is a substitution mutation (single gene)?
When on Nucleotide is replaced with another.
What is a deletion mutation (single gene)?
A mutation where a nucleotide is removed from the DNA sequence.
What is an insertion mutation (single gene) ?
A mutation where a nucleotide is added to the DNA sequence.
What are the 3 types of nucleotide substitution mutations.
Missense, Nonsense, Splice site.
Describe a missense mutation.
Missense mutations result in one amino acid being changed for another. This may result in a non-functional protein or have little effect on the protein.
Describe a Nonsense mutation.
Nonsesne mutations result in a codon for a specific amino acid being changed to a premature stop codon. This results in a shorter protein being produced.
Describe a splice site mutation.
Splice site mutations result in some introns being retained and/or some exons not being included in the mature transcript.
What is the type of mutation caused by insertions or deletions?
Frame shift.
Describe a Frame shift mutation.
All the codons and all the amino acids after the mutation are changed. This has a major effect on the structure of a protein.
What are the 4 types of chromosome mutations?
Deletion.
Inversion.
Duplication.
Translation.
Describe Chromosome deletion mutation.
A section of the chromosome is deleted.
Describe chromosome duplication mutation.
A section of a chromosome is added from its homologous partner.
