MIMG 101: Final Exam Questions and
All Correct Answers 2026-2027
Updated.
sigma factor - Answer 1. Confers tight binding to the promoter
2. Without this, the holoenzyme is only a "core"
promotor, filter-binding assay - Answer Experiments to determine that *sigma factor* allows
for tight binding to the ________________:
1. Experiment where core vs. holoenzyme was allowed to bind to radiolabelled DNA, and
measured rate at which each jumped onto nonradioactive DNA
2. Core jumped off radioactive DNA at a much higher rate
3. Doing a ____________________________ saw consistent counts with holoenzyme, but
inconsistent counts with the core
RpoS - Answer A sigma subunit that drives the transcription of a lot of stationary phase
genes; presence of these is absent when cells are in the growing phase.
28, FlgM, FlgM - Answer 1. Sigma _____ drives transcription of late flagellar proteins, like
flagellin and the cap.
2. _______ binds to this when the early flagellar proteins are being assembled so sigma factor
can't go to promoter
3. When majority of flagella is made, _________ is pumped out and freed from sigma factor so
cap and flagellin can be made
enzymatic - Answer Fastest cut off point for regulation of activity is at the
__________________ level (prevent conversion of substrate into product), which will allow the
blocking of regulatory process regardless of how many proteins and mRNA are already present.
inverted repeats - Answer 1. Transcription factors are dimers that bind to
___________________ in the major grooves and along phosphate backbones.
2. Helix-turn-helix: contains stabilizing helix that dimerizes and recognition site that binds DNA
3. Leucine finger
4. Zinc finger
trp - Answer 1. In absence of __________, repressor is inactive, so operon is active
2. _________ is a corepressor that binds to inactive repressor, and makes go conformational
change that makes repressor active
,3. repressor binds to operator and blocks __________ mRNA synthesis
4. negative feedback loop
(only one word fits all three spaces)
diauxic growth - Answer 1. cells use best carbon source first (glucose)
2. growth on lactose is slower
3. Second level of regulation of the lac operon that activates lac operon during *high* levels of
*cAMP* (*low glucose* levels)
maltose regulon - Answer 1. Activator = Mal Ti
2. Maltose binds to MalTi and induces conformation change to active MalTa (Activator)
3. MalTa binds to promoters and recruits RNA polymerase for synthesis of mal genes (P, E, K S)
(maltose metabolyzing enzymes)
4. MalTa-Polymerase complex binds to four different operons
Attenuation - Answer _______________________ of the trp operon:
1. *High Trp*: Leader sequence encodes a short *leader peptide* with 2 Trp residues is made —
> ribosome cruises through translation —> Transcription *terminates at the 3-4 hairpin*
3. *Low Trp* —> ribosome *stalls* because lack of leader peptide —> terminator sequence is
not there because of *2-3 base pairing* (there is a turn instead) —> transcription of trp
structural genes occurs
two component regulatory systems - Answer consist of:
1. sensor kinase that autophosphorylates in response to a signal and transfer of a phosphate to
a response regulator
2. response regulator will bind DNA to initiate transcription of certain genes or regulate activity
of other proteins
osmoregulation, EnvZ, OmpR - Answer 1. ___________________ is an example of a two
component system
2. the sensor kinase is ___________
3. response regulator is __________
4. At *low* osmolarity, the system will be *inactivated* because of *high OmpF* levels
(response regulator drives production of more OmpF)
5. At *high* osmolarity, the system is *activated* because of *high OmpC* levels (response
regulator blocks OmpF production but drives expression of OmpC)
, MCP, CheA, CheA, CheY, CheY, FliM, CheZ, CheY - Answer Two component system in
*chemotaxis*
1. ______________ = protein senses signals in environment; if proper signals sensed, will
phosphorylate _______________, a sensor kinase
2. _______________ = sensor kinase that will phosphorylate _______________, response
regulator
3. _______________ = response regulator that when phosphorylated, *interacts with flagella
motor proteins (______________)*, causing *tumbling*
4. _______________ = dephosphorylates __________
microarray - Answer 1. can be used to look at *transcription levels* of genes under 2
conditions (for example, with drug vs. without drug)
2. *mRNA* from each condition is isolated and *turned into cDNA*
3. DNA is hybridized to array
4. High resolution scan is taken
5. Look for relative intensities of expression (yellow spot = equal expression between 2
conditions; red spot = more mRNA from condition A; green spot = more mRNA from condition
B)
Hoof and Mouth Disease - Answer 1. Take fluid from liquid filled sacs and found that it was
transferable —> could inoculate healthy host
2. Could not be cultured
3. Disease was not due to a bacterium/unculturable
4. Could not see bacteria under microscope, so suspected disease may not be due to a
bacterium
5. Attempts to filter liquid to remove any bacteria saw that the liquid still can infect a healthy
cow, resulting in disease
TMV (tobacco mosaic virus) - Answer 1. same experimental results with hoof and mouth
disease with cattle could be seen with this type of virus
2. Crystallization of this virus confirmed existence of virus and allowed for its visualization
smallpox - Answer 1. first "vaccine" was produced for the *variola* virus that produces this
disease
2. extract from lesions of a *cow pox patient* were inserted into patient, giving him cow pox
3. however, inoculation with this virus did not cause major disease in patient
Polio - Answer 1. Humans are the only reservoir for this virus, which makes it a good
candidate for eradication
All Correct Answers 2026-2027
Updated.
sigma factor - Answer 1. Confers tight binding to the promoter
2. Without this, the holoenzyme is only a "core"
promotor, filter-binding assay - Answer Experiments to determine that *sigma factor* allows
for tight binding to the ________________:
1. Experiment where core vs. holoenzyme was allowed to bind to radiolabelled DNA, and
measured rate at which each jumped onto nonradioactive DNA
2. Core jumped off radioactive DNA at a much higher rate
3. Doing a ____________________________ saw consistent counts with holoenzyme, but
inconsistent counts with the core
RpoS - Answer A sigma subunit that drives the transcription of a lot of stationary phase
genes; presence of these is absent when cells are in the growing phase.
28, FlgM, FlgM - Answer 1. Sigma _____ drives transcription of late flagellar proteins, like
flagellin and the cap.
2. _______ binds to this when the early flagellar proteins are being assembled so sigma factor
can't go to promoter
3. When majority of flagella is made, _________ is pumped out and freed from sigma factor so
cap and flagellin can be made
enzymatic - Answer Fastest cut off point for regulation of activity is at the
__________________ level (prevent conversion of substrate into product), which will allow the
blocking of regulatory process regardless of how many proteins and mRNA are already present.
inverted repeats - Answer 1. Transcription factors are dimers that bind to
___________________ in the major grooves and along phosphate backbones.
2. Helix-turn-helix: contains stabilizing helix that dimerizes and recognition site that binds DNA
3. Leucine finger
4. Zinc finger
trp - Answer 1. In absence of __________, repressor is inactive, so operon is active
2. _________ is a corepressor that binds to inactive repressor, and makes go conformational
change that makes repressor active
,3. repressor binds to operator and blocks __________ mRNA synthesis
4. negative feedback loop
(only one word fits all three spaces)
diauxic growth - Answer 1. cells use best carbon source first (glucose)
2. growth on lactose is slower
3. Second level of regulation of the lac operon that activates lac operon during *high* levels of
*cAMP* (*low glucose* levels)
maltose regulon - Answer 1. Activator = Mal Ti
2. Maltose binds to MalTi and induces conformation change to active MalTa (Activator)
3. MalTa binds to promoters and recruits RNA polymerase for synthesis of mal genes (P, E, K S)
(maltose metabolyzing enzymes)
4. MalTa-Polymerase complex binds to four different operons
Attenuation - Answer _______________________ of the trp operon:
1. *High Trp*: Leader sequence encodes a short *leader peptide* with 2 Trp residues is made —
> ribosome cruises through translation —> Transcription *terminates at the 3-4 hairpin*
3. *Low Trp* —> ribosome *stalls* because lack of leader peptide —> terminator sequence is
not there because of *2-3 base pairing* (there is a turn instead) —> transcription of trp
structural genes occurs
two component regulatory systems - Answer consist of:
1. sensor kinase that autophosphorylates in response to a signal and transfer of a phosphate to
a response regulator
2. response regulator will bind DNA to initiate transcription of certain genes or regulate activity
of other proteins
osmoregulation, EnvZ, OmpR - Answer 1. ___________________ is an example of a two
component system
2. the sensor kinase is ___________
3. response regulator is __________
4. At *low* osmolarity, the system will be *inactivated* because of *high OmpF* levels
(response regulator drives production of more OmpF)
5. At *high* osmolarity, the system is *activated* because of *high OmpC* levels (response
regulator blocks OmpF production but drives expression of OmpC)
, MCP, CheA, CheA, CheY, CheY, FliM, CheZ, CheY - Answer Two component system in
*chemotaxis*
1. ______________ = protein senses signals in environment; if proper signals sensed, will
phosphorylate _______________, a sensor kinase
2. _______________ = sensor kinase that will phosphorylate _______________, response
regulator
3. _______________ = response regulator that when phosphorylated, *interacts with flagella
motor proteins (______________)*, causing *tumbling*
4. _______________ = dephosphorylates __________
microarray - Answer 1. can be used to look at *transcription levels* of genes under 2
conditions (for example, with drug vs. without drug)
2. *mRNA* from each condition is isolated and *turned into cDNA*
3. DNA is hybridized to array
4. High resolution scan is taken
5. Look for relative intensities of expression (yellow spot = equal expression between 2
conditions; red spot = more mRNA from condition A; green spot = more mRNA from condition
B)
Hoof and Mouth Disease - Answer 1. Take fluid from liquid filled sacs and found that it was
transferable —> could inoculate healthy host
2. Could not be cultured
3. Disease was not due to a bacterium/unculturable
4. Could not see bacteria under microscope, so suspected disease may not be due to a
bacterium
5. Attempts to filter liquid to remove any bacteria saw that the liquid still can infect a healthy
cow, resulting in disease
TMV (tobacco mosaic virus) - Answer 1. same experimental results with hoof and mouth
disease with cattle could be seen with this type of virus
2. Crystallization of this virus confirmed existence of virus and allowed for its visualization
smallpox - Answer 1. first "vaccine" was produced for the *variola* virus that produces this
disease
2. extract from lesions of a *cow pox patient* were inserted into patient, giving him cow pox
3. however, inoculation with this virus did not cause major disease in patient
Polio - Answer 1. Humans are the only reservoir for this virus, which makes it a good
candidate for eradication
