Molecular Biology Exam test quiz
and answers graded A+
What enzyme unwinds the DNA double helix at the promoter during transcription? - ANS✅✅RNA
polymerase
Other than RNA polymerase, what additional 3 classes of enzymes are needed for transcription to
occur? Mark all three correct answers - ANS✅✅- Nucleosome remodeling enzymes
- Histone chaperones
- Histone modifying enzymes
Match each RNA polymerase with its function
RNA polymerase I
RNA polymerase II
RNA polymerase III
RNA polymerase IV and V (plants only) - ANS✅✅RNA polymerase I
Transcribes ribosomal RNA (rRNA)
RNA polymerase II
Transcribes mRNA and small regulatory RNAs
RNA polymerase III
Transcribes tRNA and 5S RNA and snRNA
RNA polymerase IV and V (plants only)
Transcribes siRNA
What are two functions of the C-terminal domain of RNA polymerase II? - ANS✅✅- Involved in the
transition from initiation to elongation
,- Phosphorylated CTD recruits RNA processing enzymes that modify the RNA while it is still being
transcribed
Match the following components of the bacterial RNA polymerase with facts about each
Sigma Factor
Domain 2 of sigma factor
Domain 4
Alternative sigma factors - ANS✅✅Sigma Factor
Binds to the core enzyme to convert it to the holoenzyme
Domain 2 of sigma factor
Binds to the -10 promoter sequence
Domain 4
Binds to the -35 promoter sequence
Alternative sigma factors
Used in response to specific signals or stress conditions to express response genes.
What do eukaryotes and archaea use target their RNA polymerases to promoters? -
ANS✅✅general transcription factors
The -- subunit of TFIID binds to the TATA box element of eukaryotic promoters, whereas the --
subunits of TFIID mediate recognition of other core promoter elements or have enzymatic activities
necessary for transcription activation of gene specific transcriptional regulators. - ANS✅✅TBP; TAF
The following eukaryotic general transcription factors are placed in order of binding to the promoter.
Match the function of each GTF
TFIID: TBP subunit
, TFIIB
TFIIA
TFIIF
TFIIE
TFIIH - ANS✅✅TFIID: TBP subunit
Binds in minor groove of DNA at the TATA box that and introduces 90 degree bend in the DNA that
interacts with regulatory factors
TFIIB
Recognizes BRE promoter element; binds asymmetrically to control direction of transcription.
Stabilizes early transcribing complex
TFIIA
Further enhances TBP and TFIIB interactions with DNA
TFIIF
Present in a complex with RNA polymerase; both recruited after TFIIA. Suppresses non-specific DNA
binding
TFIIE
Recruits TFIIH
TFIIH
Uses ATP to power promoter unwinding and phosphorylates the CTD of RNA polymerase subunit
Rpb1
How does the Mediator complex assist in the activation of many RNA polymerase II transcribed
genes? - ANS✅✅Interacts with regulatory proteins that bind upstream of the promoter region
and answers graded A+
What enzyme unwinds the DNA double helix at the promoter during transcription? - ANS✅✅RNA
polymerase
Other than RNA polymerase, what additional 3 classes of enzymes are needed for transcription to
occur? Mark all three correct answers - ANS✅✅- Nucleosome remodeling enzymes
- Histone chaperones
- Histone modifying enzymes
Match each RNA polymerase with its function
RNA polymerase I
RNA polymerase II
RNA polymerase III
RNA polymerase IV and V (plants only) - ANS✅✅RNA polymerase I
Transcribes ribosomal RNA (rRNA)
RNA polymerase II
Transcribes mRNA and small regulatory RNAs
RNA polymerase III
Transcribes tRNA and 5S RNA and snRNA
RNA polymerase IV and V (plants only)
Transcribes siRNA
What are two functions of the C-terminal domain of RNA polymerase II? - ANS✅✅- Involved in the
transition from initiation to elongation
,- Phosphorylated CTD recruits RNA processing enzymes that modify the RNA while it is still being
transcribed
Match the following components of the bacterial RNA polymerase with facts about each
Sigma Factor
Domain 2 of sigma factor
Domain 4
Alternative sigma factors - ANS✅✅Sigma Factor
Binds to the core enzyme to convert it to the holoenzyme
Domain 2 of sigma factor
Binds to the -10 promoter sequence
Domain 4
Binds to the -35 promoter sequence
Alternative sigma factors
Used in response to specific signals or stress conditions to express response genes.
What do eukaryotes and archaea use target their RNA polymerases to promoters? -
ANS✅✅general transcription factors
The -- subunit of TFIID binds to the TATA box element of eukaryotic promoters, whereas the --
subunits of TFIID mediate recognition of other core promoter elements or have enzymatic activities
necessary for transcription activation of gene specific transcriptional regulators. - ANS✅✅TBP; TAF
The following eukaryotic general transcription factors are placed in order of binding to the promoter.
Match the function of each GTF
TFIID: TBP subunit
, TFIIB
TFIIA
TFIIF
TFIIE
TFIIH - ANS✅✅TFIID: TBP subunit
Binds in minor groove of DNA at the TATA box that and introduces 90 degree bend in the DNA that
interacts with regulatory factors
TFIIB
Recognizes BRE promoter element; binds asymmetrically to control direction of transcription.
Stabilizes early transcribing complex
TFIIA
Further enhances TBP and TFIIB interactions with DNA
TFIIF
Present in a complex with RNA polymerase; both recruited after TFIIA. Suppresses non-specific DNA
binding
TFIIE
Recruits TFIIH
TFIIH
Uses ATP to power promoter unwinding and phosphorylates the CTD of RNA polymerase subunit
Rpb1
How does the Mediator complex assist in the activation of many RNA polymerase II transcribed
genes? - ANS✅✅Interacts with regulatory proteins that bind upstream of the promoter region
