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WorksheetsGenomics - L7
Total questions: 62
Worksheet time: 31mins
Name
Class
Date
1.
What does RNA polymerase consist of?
a)
A single polypeptide chain
b)
DNA-binding motifs
c)
Multiple subunits that form a core enzyme
d)
A ribosome and tRNA
2.
What is a promoter?
a)
The enzyme that transcribes DNA
b)
A short RNA primer
c)
A DNA sequence that signals where RNA polymerase should bind
d)
A protein-binding domain
3.
How does RNA polymerase use the promoter?
a)
To terminate transcription
b)
To replicate the DNA strand
c)
As a binding site to initiate RNA synthesis
d)
As a scaffold for splicing
4.
What is transcription?
a)
Replication of RNA from DNA
b)
Synthesis of DNA from protein
c)
Synthesis of RNA using DNA as a template
d)
Translation of DNA into protein
5.
What does initiation in transcription refer to?
a)
Cleavage of DNA strands
b)
The process of extending the RNA chain
c)
The process where RNA polymerase binds to promoter and begins RNA synthesis
d)
Translation of RNA into protein
6.
What is elongation in transcription?
a)
RNA polymerase leaves the promoter and synthesizes RNA
b)
DNA is replicated
c)
Proteins are translated
d)
Splicing of exons occurs
7.
What is termination in transcription?
a)
Binding of ribosomes to mRNA
b)
Cleaving exons
c)
Ending RNA synthesis and releasing RNA polymerase
d)
Removal of introns
8.
Which of the following is NOT a subunit of E. coli RNA polymerase?
a)
Alpha
b)
Beta
c)
Sigma
d)
Theta
9.
Which are the largest subunits of RNA polymerase?
a)
Alpha and Omega
b)
Beta and Beta'
c)
Sigma and Rho
d)
Delta and Lambda
10.
Which RNA polymerase subunit can be separated from the rest?
a)
Alpha
b)
Beta
c)
Sigma
d)
Beta'
11.
What can the core RNA polymerase enzyme do on its own?
a)
Transcribe structured mRNA
b)
Transcribe efficiently from promoters
c)
Bind to any promoter with specificity
d)
Transcribe only nicked or denatured DNA
12.
What is a holoenzyme?
a)
Sigma subunit only
b)
RNA polymerase core plus sigma factor
c)
Only the core enzyme without cofactors
d)
DNA with attached RNA polymerase
13.
What does the sigma factor do for RNA polymerase?
a)
Terminates transcription
b)
Splices RNA
c)
Allows recognition of promoter sites
d)
Synthesizes primers
14.
Can RNA polymerase transcribe DNA without sigma factors?
a)
No, never
b)
Yes, but non-specifically at nicks and gaps
c)
Only in eukaryotes
d)
Only after translation
15.
How does the holoenzyme bind DNA initially?
a)
Tightly with open DNA
b)
Loosely, forming a closed promoter complex
c)
Irreversibly to RNA
d)
At replication origins
16.
What happens when the holoenzyme finds a promoter?
a)
It begins translation
b)
It denatures RNA
c)
It melts DNA to form an open promoter complex
d)
It splices out introns
17.
What is the structure of the bacterial promoter recognized by RNA polymerase?
a)
Poly-A tail
b)
GC box
c)
-10 and -35 elements
d)
Enhancer and silencer
18.
What is the -10 box?
a)
10 bases downstream from the start
b)
A 6–7 bp region ~10 bases upstream from transcription start site
c)
A part of the ribosome-binding site
d)
A hairpin terminator
19.
What is the -35 box?
a)
A repeated sequence downstream
b)
Region around 35 bases upstream of the transcription start site
c)
Sequence where elongation begins
d)
DNA-binding site for tRNA
20.
What are the consensus sequences for the -10 and -35 boxes?
a)
CGCGCG and ATATAT
b)
TATAAA and AGCTAG
c)
TATAAT and TTGACA
d)
TTATT and GGCTCC
21.
What type of mutation weakens RNA polymerase promoter binding?
a)
Up mutation
b)
Deletion mutation
c)
Down mutation
d)
Inversion mutation
22.
What type of mutation strengthens RNA polymerase binding to a promoter?
a)
Down mutation
b)
Up mutation
c)
Missense mutation
d)
Insertion mutation
23.
Does a promoter need to perfectly match the consensus sequence to function?
a)
Yes, or it won’t bind
b)
No, some deviation is tolerated
c)
Only in eukaryotes
d)
Only in the presence of activators
24.
What is an UP element?
a)
A protein enhancer
b)
A downstream transcription terminator
c)
A region upstream of the -35 box that enhances transcription
d)
A type of intron
25.
What do UP elements do?
a)
Inhibit transcription
b)
Bind ribosomes for translation
c)
Stimulate transcription up to 30-fold
d)
Terminate transcription early
26.
Which of the following is an example of a gene that uses an UP element?
a)
Luciferase
b)
RNA polymerase gene
c)
rRNA genes in E. coli
d)
Histone gene
27.
Which statement about transcription initiation is true?
a)
RNA polymerase skips the promoter and starts downstream
b)
It creates long transcripts before leaving the promoter
c)
It first produces short abortive transcripts
d)
DNA is unwound after elongation begins
28.
What is the first step of transcription initiation?
a)
Promoter clearance
b)
Elongation
c)
Closed promoter complex formation
d)
Ribosome assembly
29.
What happens during the second step of transcription initiation?
a)
Promoter binding tightens
b)
Transcription stops
c)
DNA melts and forms an open complex
d)
Sigma is released
30.
What occurs after the polymerase incorporates the first few nucleotides?
a)
DNA replication begins
b)
Promoter clearance takes place
c)
Introns are spliced
d)
Translation begins
31.
What does promoter clearance mean?
a)
The polymerase stalls at the promoter
b)
The transcript becomes long enough to form a stable hybrid and polymerase moves forward
c)
The promoter is excised
d)
DNA is degraded
32.
What completes the initiation phase of transcription?
a)
Ligase seals the transcript
b)
Sigma binds to tRNA
c)
RNA polymerase transitions to elongation after promoter clearance
d)
Helicase removes nucleotides
33.
What is the function of the sigma subunit?
a)
Catalyzes phosphodiester bond formation
b)
Causes tight binding between RNA polymerase and promoter regions
c)
Terminates transcription
d)
Binds tRNA
34.
What is the transcription bubble?
a)
The space between exons and introns
b)
The region where DNA is denatured during transcription
c)
A pocket formed during translation
d)
A loop of circular DNA
35.
Do all bacteria have the same number of sigma factors with conserved homology?
a)
Yes, it is universal
b)
No, the number and sequences vary across species
c)
Only in Gram-positive bacteria
d)
Only in extremophiles
36.
The sigma factor mainly recognizes which promoter regions?
a)
+1 and +30
b)
Shine-Dalgarno sequence
c)
-10 and -35 elements
d)
Splice acceptor sites
37.
The alpha subunit of RNA polymerase primarily interacts with which region?
a)
Coding sequence
b)
TATA box
c)
UP element
d)
Poly-A tail
38.
What effect does the alpha subunit binding to the UP element have?
a)
Reduces RNA stability
b)
Inhibits transcription
c)
Enhances interaction between polymerase and promoter, increasing transcription
d)
Prevents translation
39.
Define elongation in transcription.
a)
RNA polymerase releases the DNA template
b)
Nucleotides are added sequentially to form the RNA strand
c)
DNA is methylated at CpG sites
d)
RNA is translated into protein
40.
What subunits are involved in phosphodiester bond formation during elongation?
a)
Sigma and alpha
b)
Alpha and omega
c)
Beta and Beta'
d)
Alpha and gamma
41.
What is the shape of the RNA polymerase core enzyme?
a)
Hourglass
b)
Ring
c)
Crab claw
d)
Helix
42.
What is found in the catalytic channel of RNA polymerase?
a)
DNA helicase
b)
Magnesium ion (Mg²⁺)
c)
Potassium chloride
d)
Fluorescent dyes
43.
What does rifampicin do?
a)
Binds ribosomes to inhibit translation
b)
Enhances elongation rate
c)
Inhibits transcription initiation by binding to RNA polymerase
d)
Binds DNA to increase melting
44.
What subunit does DNA bind most strongly during transcription initiation?
a)
Alpha
b)
Sigma
c)
Beta
d)
Omega
45.
What enzyme helps relax supercoiling during transcription?
a)
Ligase
b)
Polymerase III
c)
Topoisomerase
d)
Kinase
46.
Which of the following about elongation is incorrect?
a)
Polymerase frequently pauses
b)
Elongation is a uniform and continuous process
c)
Backtracking can occur
d)
Pauses help coordinate with translation
47.
What is the function of transcriptional pausing?
a)
Allows translation to keep pace
b)
Causes degradation of mRNA
c)
Prevents DNA replication
d)
Activates promoter clearance
48.
What causes the DNA-RNA hybrid to destabilize in intrinsic termination?
a)
U-rich coding sequence
b)
Long GC content
c)
Hairpin loop upstream of a string of Ts
d)
Lack of sigma factor
49.
What happens at a string of Ts during intrinsic termination?
a)
Ribosomes bind
b)
RNA polymerase pauses
c)
Helicase is recruited
d)
Sigma factor is replaced
50.
What structure is formed by inverted repeats in intrinsic terminators?
a)
A poly-A tail
b)
An R-loop
c)
A DNA bubble
d)
A hairpin loop
51.
What is special about a transcript containing inverted repeats?
a)
It is self-complementary
b)
It cannot be transcribed
c)
It binds the ribosome directly
d)
It contains methylated CpGs
52.
Which of the following about Rho-dependent termination is incorrect?
a)
It requires a string of Ts
b)
Rho binds to the RNA transcript
c)
Rho has helicase activity that unwinds the RNA-DNA hybrid
d)
It depends on an auxiliary factor
53.
What does RNA polymerase consist of in bacterial transcription?
a)
DNA and tRNA
b)
A single protein
c)
A core enzyme plus sigma (σ) factor
d)
Ribosomes and RNA
54.
What is the role of the sigma factor in bacterial transcription?
a)
Elongates RNA
b)
Splices RNA
c)
Recognizes and binds to promoters
d)
Adds poly-A tail
55.
Where are the conserved promoter regions located?
a)
At the 3’ end of the gene
b)
+10 and +35 downstream
c)
-10 and -35 upstream of the transcription start site
d)
In the coding region
56.
What happens during transcription initiation?
a)
Ribosomes bind RNA
b)
RNA polymerase binds the promoter, melts DNA, and starts RNA synthesis
c)
RNA polymerase releases the transcript
d)
The sigma factor is degraded
57.
During elongation, what part of the RNA polymerase is responsible for synthesizing RNA?
a)
Sigma factor
b)
Core enzyme
c)
Helicase
d)
DNA ligase
58.
When does termination of transcription occur?
a)
When the ribosome stalls
b)
When DNA replication finishes
c)
When RNA polymerase reaches a termination signal
d)
When the sigma factor re-binds
59.
What happens to the RNA molecule at the end of transcription?
a)
It is exported from the nucleus
b)
It is translated immediately
c)
It is released from the RNA polymerase
d)
It forms a loop and rebinds
60.
Which of the following is not a type of bacterial transcription terminator?
a)
Rho-dependent
b)
Hairpin-dependent
c)
Rho-independent
d)
Intrinsic
61.
What is a key feature of rho-independent termination?
a)
Requires ATP and helicase
b)
Requires a rho protein
c)
Functions without protein assistance
d)
Occurs only in eukaryotes
62.
What is a key feature of rho-dependent termination?
a)
It requires a protein to unwind RNA-DNA hybrid
b)
Occurs only at poly-A signals
c)
Does not require a terminator sequence
d)
Happens before elongation
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