RNA Processing

Question 1

What is the difference between exons and introns?

Answer 1

Exons are coding sequences whereas introns are non-coding regions

Question 2

How is RNA modified? (4)

Answer 2

Capping at 5’ end (methylated guanine), addition of poly tail at 3’ end, removal of introns and RNA editing

Question 3

What is intron removal catalysed by?

Answer 3

Splicosome, made of small ribonucleoproteins and proteins

Question 4

Why do eukaryotes have introns? (4)

Answer 4

Some miRNA’s come from introns, alternative splicing can generate different types of mRNA (different polypeptides), role in evolution and exons often code for a domain in a multidomain peptide chain.

Question 5

What is RNA editing?

Answer 5

Where information changes at the level of mRNA

Question 6

What are poly A tails created by?

Answer 6

Poly A Polymerase

Question 7

What does alternative splicing mean?

Answer 7

by skipping exons, a gene could have multiple functions