Mutations Flashcards
(21 cards)
What is a nonsense mutation?
The substitution of a singular amino acid codon for a stop codon
What is a frameshift mutation?
It is when the reading frame of the mRNA is altered in some way
Gains or losses of base pairs that are not a multiple of threee will cause ……. and create ……… …… …..
It will cause frameshifts and create premature termination codons
mRNA that contains premature termination codons are degraded by what?
Nonsense mediated decay
Mutations at intron slice sites usually result in what?
Skipping of the exon immediately adjacent to the mutation
What is tautomeric shifts and what do they result in?
Tautomeric shifts occur when the four bases in DNA change due to a proton briefly changing position. The rare tautomeric forms pair incorrectly eg C-A and T-G
Slippage during DNA replication results in the …… of one nucleotide on the new strand
Ommision
What is UV light’s effect on DNA?
It causes the formation of thymine dimers
Give an example of a chemical mutagen that cause base changes.
Nitrous acid
EMS
IQ
How is most of DNA repairs dealt with?
By DNA polymerase’s proof reading ability
How are damaged bases repaired?
Base excision repair
Inherited breast cancer involves which two genes?
BRCA1 and BRCA2
Failure of DNA repair mechanisms results in …..
Cancer
What is the difference between a proto oncogene and an oncogene?
A proto oncogene is a gene that has the potential to cause cancer and if mutated will produce an oncogene
An oncogene is a gene that causes cancer
What affect do alkylating agents have on DNA?
They remove a base
What affect do X-rays have on DNA?
They break chromosomes
What does wild type mean?
It means the most common trait/allele/etc in the population
Oncogenes are usually involved in ………
In control of cell division
What is array comparative generic hybridisation used for?
It is used to screen for sub-microscopic chromosomal deletions for which the location cannot be deduced from the patient’s phenotype
What is p53?
A transcription factor that monitors repair of damaged DNA and if damage is too severe, promotes apoptosis
What is a missense mutation?
One amino acid being substituted for another as a result of a single base mutation
