20-22 Transcription and its Control Flashcards
What is the most abundant type of RNA in a cell? What type of RNA polymerase does this?
rRNA from RNA polymerase I
What are the five main eukaryotic RNA polymerases?
- I
- II
- III
- Mitochondrial
- Chloroplast
What are some subunits in common between the three eukaryotic RNA polymerases (I - III)?
?
Which RNA polymerase is most similar in both prokaryotes and eukaryotes?
RNA polymerase II shares many similarities in its core sequence.
- Mitochondrial RNA polymerase
- Chloroplast RNA polymerase
Why is RNA polymerase I barely regulated?
Because it is responsible for transcribing pre-rRNA genes (except for 5S-rRNA). And the cell always needs more ribosomes.
What is TBP?
TATA binding protein
- a transcription factor
- Part of RNA polymerase I
Where is eukaryotic RNA polymerase I active?
The nucleolus
Does a membrane surround the nucleolus?
No, it is simply a region of the nucleus where ribosomes are built and rRNA genes are located.
What RNA polymerase transcribes small RNA genes?
RNA polymerase III
How are eukaryotic RNA pol III promoters unusual?
They can be located within the gene that they promote
Which eukaryotic RNA polymerase is inhibited for ribosome building? How?
RNA Pol III
- 5S rRNA can inhibit transcription of itself and therefore regulate ribosome production
Which RNA polymerase transcribes mRNA genes and some snRNAs in eukaryotes?
RNA polymerase II
What is TATA binding protein (TBP)?
- Binds with TATA box (-20/-30 upstream) in eukaryotic transcription
-
What are cis elements?
Part of DNA sequence
What are trans elements?
Non-DNA (eg. proteins, mRNA etc.)
