Mutations

Question 1

What is the relationship between changes in nucleotides and the amino acid sequence?

Answer 1

Change in the nucleotide sequence can cause different amino acids to be coded for.

Question 2

What can a change in amino acid cause?

Answer 2

A change in shape and therefore function

Question 3

What are the types of point mutations?

Answer 3

Silent
Missense
Nonsense

Question 4

What is a transition mutation?

Answer 4

A base is swapped for the SAME type of base. eg purine to purine

Question 5

What is a transversion mutation?

Answer 5

A base is swapped for a DIFFERENT type of base eg purine to pyramidine

Question 6

How can point mutations in non coding regions of DNA cause problems?

Answer 6

Can alter binding sites, promoter sequences and splice sites

Question 7

What is an insertion?

Answer 7

A sequence is added to the DNA

Question 8

What is a deletion?

Answer 8

A sequence is removed from the DNA

Question 9

What can insertions/deletions cause?

Answer 9

Frameshift mutations

Question 10

What is a silent mutation?

Answer 10

A mutation that does not alter the amino acid specified

Question 11

What is a missense mutation?

Answer 11

A mutation that replaces one amino acid with another

Question 12

What is a nonsense mutation?

Answer 12

A mutation that change the amino acid specified to a stop codon

Question 13

What is a frameshift mutation?

Answer 13

Addition or subtraction of nucleotides not in multiples of 3 (Alters how the DNA is read)

Question 14

How can spontaneous mutations occur?

Answer 14

There may be an error in DNA replication

Bases have slight instability

Question 15

What does the rate of spontaneous mutations depend on?

Answer 15

Size

Sequence

Question 16

What can cause induced mutations?

Answer 16

Chemicals and Radiation - Mutagens and carcinogens

Question 17

What do alkylating agents do to DNA?

Answer 17

Remove a base

Question 18

What do Acridine agents do to DNA?

Answer 18

Add or remove a base

Question 19

What do X rays do to DNA?

Answer 19

Break chromosomes

Delete nucleotides

Question 20

What does UV radiation do to DNA?

Answer 20

Creates thymidine dimers

Question 21

Define Mutation

Answer 21

A change in the nucleotide sequence due to addition, deletion or rearrangement of nucleotides

Question 22

Define Wild Type

Answer 22

The trait that is most common in that population

Question 23

Define Mutant phenotype

Answer 23

A phenotype that differs from the common or wild type phenotype in the population

Question 24

Define Mutant allele

Answer 24

An allele that differs from the common allele in the population

Question 25

What are germline mutations?

Answer 25

Mutations that have the possibility of being passed on through the germline

Question 26

What is mismatch repair?

Answer 26

Enzymes detect nucleotides that don’t base pair in newly replicated DNA. The incorrect base paired is excised and replaced.

Question 27

Define excision repair

Answer 27

Damaged DNA is removed by excision of bases and replacement by DNA polymerase.

Question 28

What can nucleotide excision repair?

Answer 28

UV Damage and some carcinogens

Question 29

What can base excision repair?

Answer 29

Oxidative damage

Question 30

What does protein p53 do?

Answer 30

Monitors the DNA damage in a cell and promotes apoptosis if it is too severe

Question 31

How is DNA damaged linked to cancer?

Answer 31

If the DNA is damaged to the extent that apoptosis doesn't occur or leads to uncontrolled cell growth cancer cells can be created

Question 32

What is destroyed in Sickle cell disease?

Answer 32

The restriction site for the enzyme MstII

Question 33

When would you use Southern blotting to detect genetic mutations?

Answer 33

To analyse larger segments of DNA within and around a gene. Eg triplet code repeat in Huntington's disease

Question 34

When would you use Array Comparative Genomic Hybridisation (Array CGH) to detect genetic mutations?

Answer 34

For sub-microscopic chromosomal deletions for which the location (locus) cannot be deduced from the patient’s phenotype