How does a retroviruse reproduce?
Nuclear fission
Reverse transcription onto host genome
Binary fission
Reverse Transcriptase is vital for RNA retroviruses to replicate
The viral protein P is used for what?
Packaging signal for making virus particles
Capsid protein
For genome expression
Gag is the gene for envelope proteins
Which of the following can be directly translated?
+ve sense RNA
-ve sense RNA
What protein converts viral genomes into a version host cells can transcribe?
RNA dependent RNA polymerase
DNA dependent RNA polymerase
DNA dependent DNA polymerase
RNA dependent DNA polymerase
The Transcriptosome is the cell repetoire of proteins
What is the role of enhancers?
To make proteins more efficient
To make transcription of a gene more likely
To increase cell division
Name the types of enhances possible
Upstream
Adjactent
Downstream
Internal
Introns can make up to 2% of the gene
Assuming the middle segment is an intron, what is found at the 5' and 3' splice sites of the intron?
3'- G-T 5'- Pyrimidine tract
5' - G-U 3' - Pyrimidine tract & A-G
5' - Pyrimidine tract & A-T 3' G-A
How is the 5' intron splice site cleaved?
Hydroxyl attack by an adenine
Hydroxyl attack by a pyrimidine from the 5' exon splice site
The 5' exon splice site attacks the 3' intron splice site
The 5' is cleaved and the intron loops on itself- what removes the intron totally?
The 5' exon attacks the 3' splice site
The 3' exon attacks the 5' splice site
The 3' exon attacks itself
What is the roles of snRNA?
Help for splicosome
Resist formation of the splicosome
Remove intron after splicing
Twintrons are introns within introns
Which is spliced out first?
Introns
Twintrons
GpG islands are found near transcriptionally inactive human genes
Name the two theories concerning introns
Introns are ancient and are gradually being lost
Introns are new and are gradually being accumulated
What does snoRNA stand for?
Small nuclear RNA
Small nullifying RNA
Small nucleolear RNA
snoRNA causes RNA to be acetylated
SnoRNA binds to the RNA to be modified
What can SnoRNA binding lead to?
The modification of bases
The destruction of the mRNA
The replication of the mRNA
There are few miRNA's, but they are very large
What is the role of miRNA
mRNA silencing
Prevent mRNA degredation
Inhibit transcription
Once the miRNA is transcribed, what structures form?
Cruciforms
Holliday junctions
Stem-loop junctions
What enzyme have these miRNA precursors NOT been cut by?
Drosher
Dicer
Once complete, where do these miRNA structures do?
Binds to 5' end of mRNA to prevent ribosome binding
Bind to region between polyA tail and gene, causing cleavage of polyA tail
Bind in centre and cause mRNA looping
siRNA stands for Short Interfering RNA
What is the main role of siRNA?
Protection against RNA viruses
Protection against oncogenes
Protection against bacteria
Where and to what does siRNA bind?
mRNA of viral genome
mRNA of bacterial genome
mRNA of human genome
On transcribing region
On poly-A tail
siRNA binds to mRNA in a double stranded form
Which of the following could be used as a gene therapy?
miRNA
siRNA
snRNA
snoRNA
This RNA gene therapy works by making a dsRNA version of a gene in the cell; this will be cleaved to siRNA which will destroy ALL mRNA for that gene
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