Mutations

Question 1

What is a nonsense mutation?

Answer 1

The substitution of a singular amino acid codon for a stop codon

Question 2

What is a frameshift mutation?

Answer 2

It is when the reading frame of the mRNA is altered in some way

Question 3

Gains or losses of base pairs that are not a multiple of threee will cause ……. and create ……… …… …..

Answer 3

It will cause frameshifts and create premature termination codons

Question 4

mRNA that contains premature termination codons are degraded by what?

Answer 4

Nonsense mediated decay

Question 5

Mutations at intron slice sites usually result in what?

Answer 5

Skipping of the exon immediately adjacent to the mutation

Question 6

What is tautomeric shifts and what do they result in?

Answer 6

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

Question 7

Slippage during DNA replication results in the …… of one nucleotide on the new strand

Answer 7

Ommision

Question 8

What is UV light’s effect on DNA?

Answer 8

It causes the formation of thymine dimers

Question 9

Give an example of a chemical mutagen that cause base changes.

Answer 9

Nitrous acid
EMS
IQ

Question 10

How is most of DNA repairs dealt with?

Answer 10

By DNA polymerase’s proof reading ability

Question 11

How are damaged bases repaired?

Answer 11

Base excision repair

Question 12

Inherited breast cancer involves which two genes?

Answer 12

BRCA1 and BRCA2

Question 13

Failure of DNA repair mechanisms results in …..

Answer 13

Cancer

Question 14

What is the difference between a proto oncogene and an oncogene?

Answer 14

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

Question 15

What affect do alkylating agents have on DNA?

Answer 15

They remove a base

Question 16

What affect do X-rays have on DNA?

Answer 16

They break chromosomes

Question 17

What does wild type mean?

Answer 17

It means the most common trait/allele/etc in the population

Question 18

Oncogenes are usually involved in ………

Answer 18

In control of cell division

Question 19

What is array comparative generic hybridisation used for?

Answer 19

It is used to screen for sub-microscopic chromosomal deletions for which the location cannot be deduced from the patient’s phenotype

Question 20

What is p53?

Answer 20

A transcription factor that monitors repair of damaged DNA and if damage is too severe, promotes apoptosis

Question 21

What is a missense mutation?

Answer 21

One amino acid being substituted for another as a result of a single base mutation