Brainscape's Knowledge GenomeTM

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


See full index

Biol 207 > Topic 5: Mutations > Flashcards

Topic 5: Mutations Flashcards

1
Q

Mutations are the source of…

A

Genetic variation, providing the raw material for evolution
Diseases and disorders

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

Mutations are useful for…

A

Probing fundamental biological processes

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

What is a mutation

A

A permanent change in the genetic material ie DNA seq
does not need to result in phenotypic change

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

Spontaneous vs induced mutation

A

Spont = in nature (UV)
Induced = in lab

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

Genetic variation is the result of…

A

Mutations combined with processes of recombination, independent segregation, fertilization of gametes

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

What are somatic mutations

A

Arise in somatic tissues (non-heritable mutations)

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

What are germ-line mutations

A

Arise in germline tissues/cells (sexual tissues; make gametes (eggs/sperm) -> are heritable
Mutation affects one allele or one homolog

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

Gene vs chromosomal mutations

A

Gene = alter genes - relatively small
Chromosomal = altering order or presence of genes on a chromosome - relatively large

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

Slide 7

A

Somatic vs germ-line mutations

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

Mutations that usually cause phenotypic changes

A

Mutations in protein coding genes, non-coding genes (fxnal RNA), regulatory elements

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

Types of mutations (based on molecular nature)

A

Base substitutions
Insertions and deletions

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

Types of base substitution mutations

A

Transitions
Transversions

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

Insertions and deletions can cause.. Why wouldn’t they

A

frame-shift mutations
Unless the indel occurs in a unit of 3

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

What is a transition

A

Base substitution
Substitution of a purine for a purine or of a pyrimidine for a pyrimidine

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

What is a transversion

A

Base substitution
Substitution of a pyrimidine for a purine or a purine for a pyrimidine

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

What are expanding nucleotide repeats

A

Type of in-frame indel mutation
Increases the number of copies of a set of repeated nucleotides

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

What is the fragile site

A

Associated with characteristic constriction on X chromosome

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

Forward vs reverse mutation

A

Forward = wild type -> mutant type
Reverse = mutant type -> WT

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

What are missense, nonsense, silent and neutral mutations

A

Missense = aa -> diff aa
Nonsense = sense codon -> nonsense codon (stop)
Silent = codon -> synonymous codon
Neutral = no change in fxn

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

Slide 13

A

Missense, nonsense, silent mutations

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

Two phenotypic effects of mutations

A

Loss-of-function mutation
Gain-of-function mutation

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

What is a loss-of-function mutation

A

DNA that is mutated stops its normal fxn
Straight forward relationship between genotype and phenotype

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

What is gain-of-function mutation

A

More of the same fxn or totally new fxn
Not straight forward

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

What can mutations be caused by

A
  • spontaneous replication errors
  • spontaneous chemical changes
  • chemically induced mutations
  • radiation
25
Q

Types of spontaneous replication errors

A
  • tautomeric shifts
  • non-standard base pairing
  • causes of deletions and insertions (strand slippage, unequal crossing over)
26
Q

What are tautomeric shifts

A

H moves to different N on base, causes it to bond to diff base

27
Q

Examples of non-standard base pairing

A

Wobble pairing

28
Q

What is wobble pairing

A

Non-standard base pairing where thymine binds with guanine or cytosine binds with adenine

29
Q

How are DNA lesions usually repaired

A

DNA polymerase proofreading
mismatch repair
direct and excision repair mechanisms

30
Q

What happens if lesions are not reparied

A

become replicated errors in subsequent round of DNA synthesis

31
Q

Slides 18-22***

A

Wobble, strand slippage, unequal crossing over

32
Q

Examples of spontaneous chemical changes

A

Depurination: loss of purine
Deamination: loss of amino group

33
Q

Slide 24, 25**

A

Depurination, deamination

34
Q

Mutagens of chemically induced mutations

A

Base analogs
Alkylating agents
Oxidative reaction

35
Q

E.g. of base analog, what does it do

A

5-bromouracil is an analog of thymine
If present, can be incorporated into DNA during replication in place of T

36
Q

Slide 28**

A

Base analog 5-bromouracil

37
Q

What is an intercalating agent? Causes…

A

Inserts themselves between adjacent bases in DNA, distorting the 3D structure of the helix
Causes single-nucleotide indels during DNA replication

38
Q

Examples of ionizing radiation, what does it do?

A

X-rays, gamma rays and cosmic rays
Penetrate tissue and damage DNA
- dislodge electrons
- break phosphodiester backbone (DS break-> if error in repair = mutation)

39
Q

Energy level of UV radiation vs ionizing

A

UV has less energy

40
Q

UV radiation can cause…

A

Pyrimidine dimer; two thymines block replication

41
Q

Pyrimidine dimers block…

A

Cell division
- block DNA polymerase from continuing replication
- cells get stuck in G2 = death

42
Q

How do pyrimidine dimers cause mutations

A

Specific repair mechanisms deal with them, but if mistake is made = mutation

43
Q

Slide 32***

A

The Ames Test

44
Q

What is forward genetics

A

Begins with a phenotype we try to find the genes encoding that phenotype

45
Q

What is reverse genetics

A

Begins with a gene of unknown function, induce mutations, check the effect of the mutation on the phenotype

46
Q

Slide 34

A

Forward and reverse genetics

47
Q

Steps of creating random mutations

A
  1. Apply mutagens (e.g. radiation) to model species
  2. Screen for interesting phenotypes in the F2 generation
48
Q

Slide 36

A

P0, F1 and F2 generations

49
Q

Forms of targeted mutagenesis

A

Insertion mutants
RNAi mutants
CRISPR-Cas9 system

50
Q

What is transgenic insertion mutant

A

Piece of DNA is inserted into your gene of interest using transgenic technology
Insertion acts like large insertion mutation (frameshifts if in coding region = “kockout” mutant = LOF)

51
Q

Transgenic insertion mutants mice

A

neo/tk system is often used to introduce insertion into a target gene

52
Q

Slides 39, 40**

A

Transgenic insertion mutants in arabidopsis

53
Q

What is RNAi (functions)

A

RNA interference, has two functions:
1. controls gene expr at post-transcriptional level by destroying target mRNAs
2. Protect against invading viruses by destroying viral RNAs

54
Q

Two proteins in RNAi

A

Dicer: finds and cuts dsRNA into small interfering RNAs or micro RNAs
RISC: RNA-induced silencing complex: uses RNAs as template for search and destroy (of other ssRNAs that complement with it)

55
Q

How do we silence genes with RNAi

A

Engineer transgenic organisms that produce siRNA (small interfering RNA) that will complement our gene of interest, triggers RNAi process to destroy all mRNA produced from our gene of interest

56
Q

What are knock-downs

A

In RNAi, mutant b/c some mRNAs will always escape the RISC

57
Q

What does the CRISPR/Cas9 system do

A

Combines single guide RNA with a nuclease, together they attach to specific DNA sequences and make double-stranded cuts
Repair these cuts by nonhomologous end joining or homology-directed repair, providing the means to introduce alterations to the genome

58
Q

What does the single guide RNA do in CRISPR/Cas9

A

Provides specificity through complementation

Biol 207 (22 decks)

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