Probe

Question 1

What is a probe? size? ss or ds?

Answer 1

ss dna/rna/oligo 8-50bp

Question 2

How probes are made?

Answer 2

clone/chemically

Question 3

Cloned probes characteristics?

Answer 3

long (greater specificity)
many labels tagged
-stronger signals
-greater sensitivity

Question 4

Oligonucleotides characteristics? minimum recommended length & why? labeled with how many labels?

Answer 4

chemically synthed
15-50nt
20nt
11

Question 5

Can a AA seq. be used to get oligos? what happens then?

Answer 5

degenerate sequences

Question 6

Drawbacks of cloned probes

Answer 6

as they are ds… denature.. can complement itself…

Question 7

Advantages of oligo. probes?

Answer 7

small - high c can be used
ss
versatile
much can be synthed
so cost effective
can be used for long p of time
low complexity
short time hybridization

Question 8

Disadvantage of oligo. probes?

Answer 8

low sensitivity - only 1 label

Question 9

What is the advantage of RNA probes?

Answer 9

higher signal/noise ratio.

signal intensity compared to the bg

Question 10

How RNA probes are synthesized?

Answer 10

invitro transcription of inserts

- using plasmid dna & rna pol.

Question 11

What is meant by specific activity of probes?

Answer 11

radio by unit na amount

Question 12

Why RNA have high specific activity?

Answer 12

in-vitro trans

Question 13

higher the specific activity, higher the…?

Answer 13

sensitivity of hybri. assay

Question 14

Why RNA probes aren’t a popular option?

Answer 14

RNA’s prone to degradation
- ubiquitous RNAses
extra precautions