4-1: Transcription Flashcards

1
Q

What is the coding strand?

A

The strand that not used as the template by RNA pol, but will match the RNA transcript

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the template strand?

A

Used by RNA pol to make the RNA, complimentary to the RNA made

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What subunits make up RNA polymerase (core enzyme)

A

alpha subunit x2
Beta
Beta’
Omega

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the holoenzyme made up of, what does it do

A

Sigma factor (subunit) plus core enzyme
Recognize promoter sequences and will dissociated from the core enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the core enzyme do

A

Unwinds DNA, forms transcription bubble, Builds RNA using NTPs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When is transcription terminated

A

When RNAp encounters a transcriptional terminator it dissociates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two transcriptional terminators

A

Intrinsic (rho-independent) terminators

Rho-dependent terminators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the mechanism that intrinsic (rho independent) terminators use?

A

RNA hairpin forms, followed by string of ‘U’ residues (pause signal). Hairpin forces RNAp off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the mechanism that rho dependent terminators use?

A

Protein called Rho binds RNA as it is transcribed, causes RNAp to dissociate after encountering certain sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do promoters do?

A

Guide transcriptional initiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What dictates whether or not a region acts as a promoter/if the promoter is active?

A

Sigma factors
Regulatory proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the most common sigma factor

A

sigma^70 (RpoD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What two sequences does RpoD recognize

A

TTGACA and Pribnow box.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is the TTGACA found?

A

35 bp upstream from the transcription start site (+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the sequence for the Pribnow box? Where is it found?

A

TATAAT. Found 10 bp upsteream from +1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the transcriptional start site identified as?

17
Q

What do negative numbers from the transcriptional start site mean?

A

Located upstream from the start site. Eg. Pribnow box is -10 upstream

18
Q

What do positive numbers from the transcriptional start site mean?

A

Downstream.

19
Q

What are the three major classes of RNAs

A

Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

20
Q

What kind of RNA makes up ~95% of a growing cell

A

rRNA, tRNA

21
Q

what are the two regions of mRNA

A

Open reading frames (translated)
Untranslated regions (UTRs)

22
Q

What are polycistronic mRNAs

A

mRNA that encode multiple ORFs

23
Q

How are polycistronic mRNAs arranged. Why?

A

Into an operon. So they can be cotranscribed

24
Q

The ORF spans from…

A

The start codon (e.g. ATG) to the stop codon (e.g. TAA)

25
The 5'UTR spans from which regions? What does it contain?
+1 to start codon. Contains ribosome binding site
26
3' UTR spans from which regions? What does it contain?
Stop codon to final transcribed residue. Contains transcriptional terminator sequences.
27
How is transcription different in eukaryotes?
3 RNA polymerases More complex RNAp (12+ subunits) Euk RNA pol need TFs to recognize the promoters No operons
28
What is eukaryotic RNA pol II responsible for?
Producing mRNA that encodes proteins
29
What is an example of a promoter sequence in euks?
TATA box, bound by TATA TFs
30
How is Archaeal transcription similar to eukaryotes?
RNA pol resembles RNA pol II from euk that has 11-13 subunits Uses Transcription factors Also uses TATA boxes and TFs that bind TATA boxes
31
How is archaeal transcription similar to bacteria?
No 5' cap, no poly A tail, no introns No nucleus Use of operons