RNA and introns

Question 1

Explain Gene Expression in Eukaryotes ?

Answer 1

1. Transcription5’ capping + 3’ polyA tailing
2. Introns loop out
3. Introns spliced out
4. mRNA transported into cytoplasm
5. mRNA translated

Question 2

Human slo gene can produce?

Answer 2

Around 500 different transcripts. Protein involved in sound reception in the cochlea

Question 3

Splicing out introns. Name the splice sites ?

Answer 3

5'-GU-3' = 5' splice site 
5'-PyPyPyPyPy-3' = Polypyrimidine tract
5'-AG-3' = 3' splice site

Question 4

Function of snRNA ?

Answer 4

Small nuclear RNA (snRNA) molecules direct the splicing of pre-mRNA to form mRNA, thus allowing for precise alignment and correct excision of introns

Question 5

What are Twintrons ?

Answer 5

Twintrons represent a special intronic arrangement in which introns of two different types occupy the same gene position. Consequently, alternative splicing of these introns requires two different spliceosomes competing for the same RNA molecule

Question 6

What is small nucleolar RNAs (snoRNA) involved in ?

Answer 6

• Involved in the chemical modification of rRNAs - Methylation and Pan-editing

Question 7

What is the role of MicroRNAs (miRNA) ?

Answer 7

MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in regulating gene expression

Question 8

What are small interfering RNA (siRNA) ?

Answer 8

Can be used to “interfere” with the translation of proteins by binding to and promoting the degradation of messenger RNA (mRNA) at specific sequences

Question 9

What is the role of RNAi ?

Answer 9

RNA interference (RNAi) is a post-transcriptional gene regulatory system that promotes gene silencing through the use of non-coding RNA molecules called microRNAs

Question 10

Splicing is a two step process which takes place within ?

Answer 10

The spliceosome