1.6 Mutations Flashcards
Define a ‘Mutation’
A random irreversible change to an organism’s DNA sequence resulting in no protein or an altered protein be produced
What are the two possible results of a mutation?
- No protein produced
- Altered Protein
How can a mutation affect the phenotype?
Mutation will result in a change to amino acid sequence meaning altered protein / no protein produced. The proteins produced determines the phenotype. This means the phenotype is altered.
What are the three types of single gene mutations?
- Substitution
- Insertion
- Deletion
What are three types of substitution mutations?
- Missense
- Nonsense
- Splice Site
What is a missense substitution mutation?
Missense - causes the change to one amino acid
What is a splice site substitution mutation?
A mutation which changes the boundaries between exons and introns, resulting in introns staying in mature transcript
What is a nonsense substitution?
A mutation when one triplet is changed to form a stop codon
A nonsense mutation results in a … being produced which results in a shorter protein.
premature stop codon.
A nonsense mutation results in a premature stop codon being produced which results in a shorter protein.
What is the result of a missense mutation?
May result in a non-functional protein or have little a effect on the protein
What kind of substitution can result in a change to the mature mRNA transcript?
Splice site - results in introns being left in and alters final protein produced
What is a frame shift mutations?
Mutation resulting in all of the codons and all of the amino acids after the mutation to be changed
What type of single gene mutations result in a frame shift mutations?
Insertion
Deletion
What are the four types of chromosome mutations?
Duplication
Deletion
Inversion
Translocation
Describe an inversion chromosome mutation
An inversion mutation is where a segment of the chromosome breaks off, is inverted 180 degrees and attaches back onto the same chromosome
Describe a duplication chromosome mutation
A section of the chromosome is duplicated from the homologous partner and genes are repeated.
What type of chromosome mutation decreases the length of the chromosome?
Deletion
What is a translocation chromosome mutation?
Segment of chromosome breaks off and attaches to its non homologous chromosome partner
Which type of chromosome mutation is most important in terms of evolutionary terms and why?
Duplication
- provides extra genetic material
- can undergo mutation
- increases chance of a new gene being created
What is the main difference between a gene mutation and a chromosome mutation?
Gene mutation - change to a single triplet of bases in a gene
Chromosome mutation - change to the gene sequence in a chromosome (structure of chromosome)
