Basic Transcription Part 5 Flashcards
1
Q
shine-delgarno sequence
A
- now called ribosome binding site
- helps first ribosome bind and translate message
2
Q
which step is the most difficult
A
- initiation
3
Q
prokaryotic transcription unit
A
- polycistronic
- > 1 gene included on transcript
- > 1 start site and stop site
4
Q
Type I RNA polymerase
A
- pre-rRNAs for 18, 5.8 and 28S rRNAs
5
Q
Type II RNA polymerase
A
- pre-mRNA
- some snRNAs
6
Q
Type III RNA polymerase
A
- pre-tRNAs
- 5S rRNA
- some snRNAs
7
Q
what transcribes most protein coding genes
A
Type II RNA pol
8
Q
organization of prokaryotic transcription unit
A
- Shine Delgarno
- Translation start codon
- Translation stop codon
9
Q
compare the subunit composition of E coli RNA polymerase with eukaryotic RNA polymerase II.
A
- E. coli has 2 alpha’s, 1 beta, 1 beta’ and one omega
- RNA pol II has 12 subunits
10
Q
what is the cleft lined with
A
- basic amino acids to bind DNA
11
Q
4 mobile elements
A
- Core
- Clamp
- Shelf
- Jaw Lobe
- move relative to each other as transcription takes place
12
Q
Core
A
- RPB 3, 10, 11, and 12 and regions of RPB 1 and 2 form active center
- comprised mainly of subunits common to all cellular polymerases
13
Q
Shelf and Jaw Lobe
A
- move relatively little and can rotate parallel to the active site cleft
14
Q
Clamp
A
- connected to the core through a set of flexible switches
- moves with a large swinging motion to open and close cleft
15
Q
TFIID
A
- binds TATA box
