Lecture 7: DNA to RNA

RNA Polymerase

-Unwinds DNA
-Selects template strand
-Adds ribonucleotides 1-by-1 to the 3' end of the RNA chain
-Does not stay bound to DNA. Unbinds as it's portion of the RNA strand exits the RNA polymerase.

consensus sequence

A portion of the RNA that is not involved in protein production but typically is involved with signaling the start or end of protein synthesis.

These regions do not have to be 100% accurate, they can be somewhat varied.

Bacterial RNA Polymerase Function

(1) A σ factor binds to RNA Polymerase which allows it to look for DNA

(2) Due to it's very weak affinity for DNA it slides back and forth to scan for the promoter region, but it has a very strong bond with the promoter region and this is when transcription begins.

(3)Initial RNA strand is slow forming until the σ factor releases

(4)Terminator (a heterotypic sequence to stop) causes the transcription to cease and release the DNA. The odd 3D structure of the RNA causes the RNA polymerase to release the RNA.

RNA Synthesis proceeds in the _________ direction

5'→3'

Eukaryotic RNA Polymerase II Function

Do we need to know this? (Lecture 7, slide 16)

Enhancer

Site that increases the likely-hood of attracting an RNA polymerase

Promoter

Site that initiates binding and the start of transcription

Eukaryotic RNA Capping

5' Cap of 7-methyl guanosine bound to the triphosphate bridge

3' Trimming of the UTR and polyadenylation (Add -AAA...)

Spliceosome

-RNA Splicing
-Removal of introns
-Occurs in the nucleus