Nucleic acid Flashcards
1
Q
Summarise viral nucleic acid
A
- Determines viral properties
- Linear or circular
- Continuous or segmented
- Usually haploid
- May contain alien nucleic acid
2
Q
Give examples of alien nucleic acid
A
- Polyomaviruses, pestiviruses: Host cell nucleic acid
- Arenaviruses: Ribosomes
- Retroviruses: onc, src genes
3
Q
Nucleic acid purification
A
- From purified virus suspension
- Proteinase K enyme digestion +
- Chloroform +
- Isoamylalcohol →
- Extraction
or
- Protein lysis/purification by chromatography
4
Q
Describe purification by chromatography
A
- Gels, filters, beads
- Quicker, simpler, less dangerous
5
Q
Describe early viral nucleic acid investigations
A
- Morphology studies
- Biochemistry studies
6
Q
Describe later viral nucleic acid investigations
A
- Manipulation
- Genetic engineering
7
Q
Investigation of RNA infectivity (RNA Polarity)
A
8
Q
What is required for the transcription of viral RNA?
A
Viral enzyme
9
Q
Give the examples of nucleic acid EM observation
A
- Electrophoresis
- Restriction endonuclease analysis
10
Q
EM observation of NA can be…
A
Linear or circular
11
Q
Electrophoresis
A
- Size:
- Circovirus = 1.7 kb
- Pox = 300 kbp
- Information is proportional to size
- Continuous NA thread
- Segmented genome
12
Q
Restriction endonuclease analysis
A
- dsDNA
- Endonucleases:
- Bacterial defence enzymes → Recognise certain sequences
- Sticky end - blunt end
- Enzyme cleavage
- Physical mapping
13
Q
Enzyme cleavage
A
- More exact size
- Smaller fragments → Handling
- Electrophoresis
- Restriction of fragment length polymorph
- ID + taxonomy
- Epidemiological investigations
14
Q
Physical mapping
A
- The localisation of cleavage sites
- Partial digestion with endonucleases
15
Q
Molecular cloning of viral DNA
A
- Propagation of virus DNA fragments in bacterial plasmids
- Mass DNA production: Quicker + cheaper
- Expression plasmids: Protein production
- Safe bacteria needed
