Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 1 - Molecule, Genes and Disease > MGD Session 9 Mutagenesis > Flashcards

MGD Session 9 Mutagenesis Flashcards

1
Q

Explain the relationship between changes in nuceleotide and amino acid sequence

A

A change in the genetic code (base sequence) can result in different amino acids being coded for.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What effect does a change in amino acid sequence have on its protein?

A

Changes it shape, so changes its function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are two types of point mutation?

A

Transition or transversion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a transition mutation?

A

Purine–>Purine
or
Pyridimine –> Pyridimine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is transversion?

A

Pyridimine –> Purine
or
Purine –> Pyrimidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are single base mutations also known as? (haircut)

A

Single Nucleotide Polymorphisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name three types of mutation other than transition?

A

SIlent, missense and nonsense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can point mutations outside of coding regions be detrimental? (3)

A

Can occur in binding sites, promoter sequence and splice sites.,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are insertions and deletions?

A

When a sequence is added or removed from dna sequence. Can be single, a few nucleotides or millions of nucleotides long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of mutation can insertions and deletions cause?

A

Frameshift mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a silent mutation?

A

A mutation that does not alter the amino acid specified (but sometimes can disrupt RNA splicing).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a missense mutation?

A

A mutation that replaces one amino acid with another. Some can be tolerated better than others, especially in non-critical regions of proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a nonesense mutation?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a frameshift mutation?

A

Addition or subtraction of nucleotides not in multiples of 3(insertions, deletions or splice site mutations. Stop codons often found

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to mRNAS which contain premature termination codons?

A

They are degraded by nonesense mediated decay, so little or no protein is produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

AUG (Met) ACG (Thr) CUA (Leu)  AUG (Met) ACG (Thr) CUG (Leu)

A

Silent mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

AUG (Met) ACG (Thr) UGG (Trp)  AUG (Met) ACG (Thr) UGA (Stop)

A

Nonesense mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

AUG (Met) ACG (Thr) GAC (Asp)  AUG (Met) ACG (Thr) GAA (Glu)

A

Missense mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

GGA (Gly) GCA (Ala) CCA (Pro) GGA (Gly)  GGA (Gly) GCC (Ala) ACC (Thr) AGG (Arg)

A

Frameshift mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens if a mutation occurs at an intron splice site?

A

Results in skipping of exon adjacent to mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When an exon is skipped due to mutation an intron splice site, what happens if it is a multiple of 3 bp?

A

The mRNA will be shortened but still in frame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When an exon is skipped due to mutation an intron splice site, what happens if it is not a multiple of 3 bp?

A

mRNA will contain PTC, resulting in nonesense mediated decay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Name three ways in which spontaneous mutations occur?

A

Slippage during replication - One strand folds back on itself and is left out of replication
Errors during DNA repair
DNA bases have slight chemical instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What two things does the rate of spontaneous mutation depend on?

A

Size and Sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is spontaneous mutation not caused by?

A

Exposure to known mutagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are induced mutations caused by?

A

Mutagens and Carcinogens - Chemicals the cause mutations and cancer respetively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Give three examplesof mutagens and their affects

A

Aklylating agents - Remove a base
Acridine agents - Add or remove a base
UV radiation - Creates thymidine dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define mutation

A

‘a change in a nucleic acid sequence, which can be the addition of one or more (or many) nucleotides [insertion], the removal of one or more (or many) nucleotides [deletions], or the rearrangement of several (or many) nucleotides’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a wild type?

A

an individual within a population displaying a wild-type trait, which is the trait that is most common in that population’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What kind of phenotype does a mutation cause?

A

A mutant phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does a mutation in a gene cause?

A

A mutant allele

32
Q

What happens if mutations occur in the germline?

A

Germline mutations

33
Q

What is mismatch repair?

A

This occurs when enzymes detect nucleotides that don’t base pair in newly replicated DNA.
The incorrect base paired is excised and replaced. These bases exist because of failure of proof reading

34
Q

Excision Repair

A

DNA damaged by external agents such a chemical mutagens is removed by excision of bases and replacement by DNA polymerase.

35
Q

Nucleotide excision repair

A

replaces up to 30 bases and is used in repair of UV Damage and some carcinogens.

36
Q

Base excision repair

A

replaces 1-5 bases and repairs oxidative damage. Fairly long patches of new DNA synthesis on repaired strand.

36
Q

Which protein is called the guardian of the genome, and what is its role?

A

p53 monitors repair of damaged DNA and if damage is too severe it promotes apoptosis

36
Q

What can be inherited which leads to increased gene mutation?

A

Mutations in the genes encoding the DNA repair proteins can be inherited. Therefore, there is an overall increase in mutations, as errors/DNA damage isn’t repaired efficiently.

36
Q

Base excision repair

A

replaces 1-5 bases and repairs oxidative damage. Fairly long patches of new DNA synthesis on repaired strand.

36
Q

How are cancerous cells produced?

A

If DNA is damaged the extent that apoptosis (programmed cell death promoted by p53 protein) doesn’t occur or the damage leads to uncontrolled growth then cancerous cells are produced.

36
Q

What enzymes can potentially be rendered non-function in order for cancer to occur?

A

Can occur as result of mutational and resultant non-functionality in mismatch repair enzymes.

36
Q

What are tumours?

A
  • Tumours are derived from individual abnormal cells.

- They arise from the lack of normal growth control.

36
Q

Which type of cell are tumours more likely to arise from?

A

cell types undergoing frequent cell division.

36
Q

What does the behaviour of a tumour depend on?

A

Cell type

36
Q

What are oncogenes responsible for?

A

Control of ceoll division

36
Q

What is the function of an oncogene

A

To stimulate/inhibit growth

36
Q

What is the role of a tumour supressor gene?

A

To protect the cell against one step on the path to cancer

36
Q

How do viruses cause cancer?

A

Carry copies of oncogenes

36
Q

What are the steps of PCR?

A
  1. DNA is denatured @ 950C for 1 minutes
  2. Anneal the primers @ 550C for 1 minute
  3. Copy the DNA @ 720C for 2 minutes
36
Q

How is PCR used to detect sickle cell disease?

A

In Sickle Cell disease the restriction site for the enzyme MstII is destroyed:
CCTGAGG  CCTGTGG
Therefore, with Gel Electrophoresis/Southern blotting the mutated gene will have less/one DNA fragments if digested with MstII, as it lacks the site.

36
Q

Why can’t straight PCR be used to analyse Cystic Fibrosis?

A

3 base deletion (No frameshift)

Loss of Phenylalanine

36
Q

When is southern blotting used?

A

when there is a need to analyse larger segments of DNA within and around a gene.

36
Q

Name two conditions southern blotting is used to analyse

A

triplet repeat disorders such as Huntington’s disease and Fragile X syndrome.

36
Q

What is array comparative genomic hybridisation used to analyse?

A

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

36
Q

How does array CGH work?

A
  • Array of DNA probes covering entire genome
    -Patient DNA and normal control DNA labelled with different coloured fluorescent tags
    Equal amounts of labbeled DNA are then hybridised to probe array
    Hybridisation signals detected and compared
36
Q

What happens when probes of normal DNA exceed that of the patients DNA?

A

the patient has a deletion of the chromosomal region from which that probe was derived.

37
Q

Which protein is called the guardian of the genome, and what is its role?

A

p53 monitors repair of damaged DNA and if damage is too severe it promotes apoptosis

38
Q

What can be inherited which leads to increased gene mutation?

A

Mutations in the genes encoding the DNA repair proteins can be inherited. Therefore, there is an overall increase in mutations, as errors/DNA damage isn’t repaired efficiently.

39
Q

How are cancerous cells produced?

A

If DNA is damaged the extent that apoptosis (programmed cell death promoted by p53 protein) doesn’t occur or the damage leads to uncontrolled growth then cancerous cells are produced.

40
Q

What enzymes can potentially be rendered non-function in order for cancer to occur?

A

Can occur as result of mutational and resultant non-functionality in mismatch repair enzymes.

41
Q

What are tumours?

A
  • Tumours are derived from individual abnormal cells.

- They arise from the lack of normal growth control.

42
Q

Which type of cell are tumours more likely to arise from?

A

cell types undergoing frequent cell division.

43
Q

What does the behaviour of a tumour depend on?

A

Cell type

44
Q

What are oncogenes responsible for?

A

Control of ceoll division

45
Q

What is the function of an oncogene

A

To stimulate/inhibit growth

46
Q

What is the role of a tumour supressor gene?

A

To protect the cell against one step on the path to cancer

47
Q

How do viruses cause cancer?

A

Carry copies of oncogenes

48
Q

What are the steps of PCR?

A
  1. DNA is denatured @ 950C for 1 minutes
  2. Anneal the primers @ 550C for 1 minute
  3. Copy the DNA @ 720C for 2 minutes
49
Q

How is PCR used to detect sickle cell disease?

A

In Sickle Cell disease the restriction site for the enzyme MstII is destroyed:
CCTGAGG  CCTGTGG
Therefore, with Gel Electrophoresis/Southern blotting the mutated gene will have less/one DNA fragments if digested with MstII, as it lacks the site.

50
Q

Why can’t straight PCR be used to analyse Cystic Fibrosis?

A

3 base deletion (No frameshift)

Loss of Phenylalanine

51
Q

When is southern blotting used?

A

when there is a need to analyse larger segments of DNA within and around a gene.

52
Q

Name two conditions southern blotting is used to analyse

A

triplet repeat disorders such as Huntington’s disease and Fragile X syndrome.

53
Q

What is array comparative genomic hybridisation used to analyse?

A

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

54
Q

How does array CGH work?

A
  • Array of DNA probes covering entire genome
    -Patient DNA and normal control DNA labelled with different coloured fluorescent tags
    Equal amounts of labbeled DNA are then hybridised to probe array
    Hybridisation signals detected and compared
55
Q

What happens when probes of normal DNA exceed that of the patients DNA?

A

the patient has a deletion of the chromosomal region from which that probe was derived.

Semester 1 - Molecule, Genes and Disease (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions