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Flashcards in Week 5 Deck (28)
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1
Q

what does siRNA means?

A

Small interfering DNA

2
Q

How does siRNA match to target?

A

Perfect match

3
Q

Is siRNA conserved across organisms? Why?

A

No. They are prone to mutations.

4
Q

Which RNA is highly conserved across organisms?

A

miRNA

5
Q

siRNA is mostly made from what?

A

retrotransposon elements

6
Q

Endogenous method of siRNA production?

A

Transposon and repeat sequences

7
Q

Exogenous method of siRNA production?

A

Viral or engineering transgene

8
Q

What both siRNA and miRNA target?

A

Themselves, in order to silence.

9
Q

How is siRNA made? (2 steps)

A

Post-transcriptional small hairpin loops or promoters on each strand, RNA polymerase and protein leads to loss of 1 strand.

10
Q

What cleaves RNA?

A

AGO.

11
Q

What miRNA does?

A

Codes for protein deactivation

12
Q

How is miRNA formed?

A

-Hairpin loop structure when one part of the transcript matches with itself (inverted repeats), open end and hairpin cleaved, AGO cleaves it.

13
Q

How does miRNA matches to target?

A

Can be perfect or imperfectly

14
Q

Which sRNA matches perfectly to target always?

A

siRNA.

15
Q

Endogenous source of miRNA?

A

Non protein coding genes

16
Q

Exogenous source of miRNA?

A

Hairpin loop RNA.

17
Q

What do plants miRNAs target?

A

Single target or only closely related sequences.

18
Q

What do animals miRNAs target?

A

Imperfect base-pairing and multiple target sites.

19
Q

What are some miRNAs associated with?

A

Determining cell fate/target regulatory genes that control developmental decisions

20
Q

Characteristic of long non-coding RNAs (lncRNAs)?

A

Devoid of evident ORFs, player in cell differentiation and development.

21
Q

Why target RNA? (2 points)

A

1 RNA –> multiple proteins.

Some proteins inaccessible to drugs.

22
Q

Effects of chemical modification of RNA

A

more stability, resistance and binding

23
Q

Morpholinos (an antisense oligonucleotide)

A

A synthetic oligonucleotide that replaces a base and acts by steric blocking mechanism (blocks translation).

24
Q

Pros of antisense oligonucleotides for RNA manipulation

A
  • Does not induce immune response

- Stable in cells

25
Q

What is the use of subtractive hybridisation?

A

Identify difference in DNA or RNA between different cell types/organisms/species

26
Q

What is subtractive hybridisation?

A

Takes cell with deletion on gene of interest, cut, separate strands and anneal to no-deletion to see homology.

27
Q

siRNA therapy

A

siRNA inhibits mRNA.

28
Q

Issues with small RNA therapy

A

Delivery is a challenge (stability, non-accessible tissues, etc.)