D1.3 Mutation & Gene Editing Flashcards

(28 cards)

1
Q

Why are knockout organisms useful to scientists studying the function of specific genes?

A

To study how a specific gene may cause/contribute to human disease

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

causes of mutation within a species

A

Meiosis, mutation and random fertilisation

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

What happens during huntingtons disease

A
  • trinucleotide repeat expansion
  • many copies of CAG are added to HTT gene
  • in chormosome 4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Sickle Cell Anemia

A

*due to single base substitution of A to T
* 6th triplet changes from GAG (GLU) to GTG (VAL)
* mRNA codon CUG to CAG
* alters AA sequence in haemoglobin
* blood cells are in sickle shape instead of biconcave disk
* takes up less O2

FYI: causes heart stroke/attack, bone malformation, pneumonia
1. long fibres poke into cell membrane = distorts shape
2. ability to carry oxygen decreases
3. block blood vessels
4. puts strain on liver as it removes cells
5. bone marrow has to continuously produce more

  • prim & second structure of Beta subunit is altered
  • quaternary structure of haemoglobin changes
  • fibres are deformed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

mutation

A

change in the genetic composition of a cell

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

single nucleotide polymorphism

A

Replacement of a single nucleotide with another, producing variation within a species.
* synonymous
* non synonymous

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

Synonymous mutation

A

change in the DNA sequence resulting in the production of the same amino acid

silent mutation

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

non synonymous

A

change in the DNA sequence resulting in the production of a different amino acid

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

Frameshift mutation

A

Mutations altering the reading frame of a DNA sequeneces triplets

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

Types of base substituation methods

A
  • nonsense= stop codon
  • missense= wrong AA
  • same sense= same AA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Causes of mutations

A
  • errors in DNA replication
  • mutagens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mutagen

A

Chemical/physical agents which have the ability to alter genetic sequences

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

Mutagen examples

A

chemical
* mustard gas
* nitrous acid
* ethyl urethane
* formaldehyde

physical
* UV
* X Ray

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

Randomness of Mutation

A
  • cytosine is most likely= spontaneous: deamination
    => loses amine group = turns to uracil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Somatic cells

A

all body cells except germ cells

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

Effects of mutations to proteins

A
  • same P produced
  • different but functioning P produced
  • non functioning P produced
  • no protein produced
  • improvement

=> genetic variation

14
Q

Pros & Cons of gene mutation

A

Pros
* better survival rate
* better adaption
ex: sickle cell = malaria resistance

Cons
* out of control cell multiplication
* mutation opf gamete = death of foetus
ex: Cystic Fibrosis, Haemophilia, Red-green color blindness, huntingtons disease

14
Q

Effects of mutations to cells

A

Somatic = disease (not passed to offspring)

germ= inhertited mutations

15
Q

Gene Mutation Diseases

A

Cystic Fibrosis, Haemophilia, Red green color blindness, Huntingtons disease

16
Q

gene knockout

A

technique in which a specific gene is intentionally removed or changed so that the expression of it is permanently prevented

17
Q

Knockout orgnaism example

A

Obese knockout mice
* leptin= hormone involved in regulating energy intake vs expernditure
* removed coding segment for leptin
=> Mice rapidly gained weight

18
Q

P53 - Knockout gene

A
  • when P53 is inactive = higher prevelance of cancerous growth
  • inhibts tumor development
19
Q

CRISPR- Cas9

A

Clustered Regularly Interspaced Palindromic Repeats
Cas9= endonuclease enzyme which cuts specific target sites

20
Q

CRISPR Mechanism

A
  1. foreign DNA that matched CRISPR spacer = corresponding crRNA molecule identifies & binds to iral sequence
  2. guides Cas9 to target DNA
  3. Cas9 makes precise cuts
  4. double strand break = can be repaired by cells DNA machienery
21
Use of CRISPR in gene editing
* RNA targets & binds to particular DNA sequnece * adapted in genetic engeneering * scientists can add, delete or modify DNA at that point
21
Ethical Implication of CRISPR
* gene therapy = treating by correction * agriculture= enhance traits * disease modelling= insight & forecast * genetic engeneering= pharma & enhance production
22
conserved dna
sequneces that remian indentical accross a species or group of species => very little genetic mutation
23
conservation hypothesis
1. Functional constraints; selective pressures that prevent the accumulation of mutations that disrupt the function of a gene or its products => unhelpful mutations wont persist 2. Slower rates of mutation ; natural selection pushes mutation rates down to a lower limit set by the power of random genetic drift rather than by intrinsic physiological limitations. => reduced levels of replication, transcription, translation.