Genetics Problems

Question

In eukaryotes, transcription termination and polyadenylation are coupled. The key shared step is cleavage of the RNA trancript just 3' of the signal sequence.

A) Describe what happens to the 5' (upstream) cleavage product.

B) Describe what happens to the 3' (downstream) cleavage product.

C) Which cleavage product becomes the RNA?

Answer 1

So in order for the messenger RNA (mRNA) to be transcribed and leave the Nucleus, 3 things must occur:

1. The 5' Cap must be placed at the 5' end to prevent endonuclease activity from "eating" the actual message at the 5' end.
2. The 3' Poly-Adenine Tail (Poly-A Tail) must be added to the 3' end to also prevent endonuclease activity from "eating" the message at the 3' end.
3. The Introns must be selectively cut from the message depending upon which protein that is needing to be produced

Once these 3 things occur, the mRNA can leave the nucleus and go to the ribosome to be translated into amino acid chains/ protein