RNA processing in eukaryotes

Where does RNA editing mostly occur?

In the nucleus

Do prokaryotes undergo extensive RNA processing?

No, only eukaryotes do

How is tRNA processed?

5’ leader and 3’ trailer cleaved, CCA is added to 3’ end, introns removed/bases modified

How is the 5’ cap made?

1. 5’ phosphate at the end is cleaved

2. GTP is used to add a 5’ to 5’ triphosphate linkage

3. Terminal G is methylated

4. 2’- OHs are methylated

What is the point of the 5’ cap and 3’ poly-A tail?

It stabilizes the mRNA and enhances translation

Is the poly(A) tail encoded by DNA?

No

What 2 letter sequence does the 5’ end and 3’ end of introns begin/end with?

5’ - GU

3’ - AG

What catalyzes the splicing of mRNA?

Spliceosome

What is a spliceosome made of?

small nuclear RNAs and proteins

What forms the catalytic center of the spliceosome?

RNAs

Are transcription and mRNA processing separate or are they coupled?

They are coupled

A RNA functioning as a catalyst is called a __________

ribozyme

Ribosomes, telomerases, and spliceosomes are all examples of _________ acting as a catalyst

RNA