DNA, RNA...Replication, Transcription, Translation Flashcards
1) Initiator protein that binds replicator in E.coli?
2) DNA helicase?
3) Single-stranded binding protein?
4) Topoisomerase?
5) DNA Pol 1
1) DNA A
2) Untwists helix
3) Prevents re-annealing
4) Relaxes strand behind the fork
5) Remove RNA primer and add DNA
In eukaryotes:
1) Pol alpha
2) Pol delta
3) Pol epsilon
1) Initiates new strands by primase
2) Lagging strand synthesis
3) Leading strand synthesis
Telomerase?
Synthesizes telomere DNA using RNA template(reverse transcriptase)
RNA can have unconventional base pairs…give an example
G-U or G-A
(these are mainly in rRNA)
1) RNA has what at the 2’ end?
2) What does it do?
1) OH
2) Prevents it from forming a B-form helix(it resembles the A-form)
T/F: Bacterial mRNA is monocistronic(codes for 1 protein only)
False. Bacterial mRNA is polycistronic…Eukaryotic mRNA is monocistronic
1) How many loops are in tRNA?
2) Which binds the codon
1) 4
2) II
1) Most abundant form of RNA in a cell?
2) Regions of DNA that contain genes for that RNA are called?
3) Mature form of that RNA consists of?
1) rRNA
2) rDNA/rRNA transcription units
3) 5.8s, 18s, 28s
1) Sigma factor?
2) 2 examples
1) Makes sure holoenzyme binds in a stable way to promoter
2) sigma 70 and sigma 32(heat, stress)
Rho-independent(type 1) vs Rho-dependent(type 2) termination?
RNA pol terminates transcription vs Rho helicase terminating transcription
Eukaryotic RNA Pol’s?
Pol 1: rRNA
Pol 2: mRNA, snRNA
Pol 3: tRNA, 5s rRNA, snRNA
RNA pol subunits?
Core: RBP 1,2,3,11
Common: RBP 5,6,8,10,12 (in all 3)
Non-essential: RBP 4,9
In which class of promoters is spacing crucial for transcription control?
Class I
1) 5’ cap enzyme?
2) 3’ Poly(A) tail enzyme?
1) guanylyltransferase(m7G)
2) Poly A polymerase
Termination of transcription in eukaryotes involves?
XRN 2 exonuclease
snRNP’s order of binding?
U1 - U2 - U4/U6 + U5 - U4 dissociates(active spliceosome)
mRNP exporter steps?
- REF recruits NXF 1, NXT1
- CBC to 5’, PABPN1 to poly (A)
Translation in bacteria?
Initiation:
- 30s has IF 1(blocks A site) and IF 3(prevents binding of 50s)
- Binds to mRNA via AUG and Shine dalgarno
- f-met tRNA + IF 2(carries GTP) binds to complex at P site
= 30s initiation complex
- 50s binds and IF’s released
Elongation:
- Aminoacyl tRNA to A site + EF
- Peptidyl transferase
- EF-G + GTP hydrolysis = translocation
Termination:
- Release factors(RF) recognize stop codons
- RF 1, UAA, UAG
- RF 2, UAA, UGA
- RF 3-GDP releases RF 1,2 and GTP hydrolysis releases RF 3
- RRF binds to A site, translocates to P, releases uncharged tRNA at E
- EF-G releases RRF and disassemble
Translation in Eukaryotes?
Initiation:
- 40s + eIF4F(cap-binding protein eIF4E) + Met tRNA scan for AUG(in Kozak sequence) and bind
- 60s binds and eIF’s displaced except eIF4F
- 80s initiation complex
- PABP II binds to eIF4G = poly (A) stimulates initiation
Elongation:
- Same as bacteria
Termination:
- eRF 1 recognizes all stop codons
- eRF 3 terminates
