BIOL 203 NUTRITION ASSESSMENT FINAL
COMPREHENSIVE EXAM 2026 STUDY
GUIDE Q&A UPDATED
⩥ A lack of which molecule would result in a cell's inability to "turn off"
genes?
A) operon
B) inducer
C) promoter
D) corepressor. Answer: D) corepressor
⩥ Which of the following, when taken up by a cell, binds to a repressor
so that the repressor no longer binds to the operator?
A) inducer
B) promoter
C) repressor
D) corepressor. Answer: A) inducer
⩥ Most repressor proteins are allosteric. Which of the following binds
with the repressor to alter its conformation?
A) inducer
B) promoter
,C) transcription factor
D) cAMP. Answer: A) inducer
⩥ A mutation that inactivates a regulatory gene of a repressible operon
in an E. coli cell would result in _____.
A) continuous transcription of the structural gene controlled by that
regulator
B) complete inhibition of transcription of the structural gene controlled
by that regulator
C) irreversible binding of the repressor to the operator
D) continuous translation of the mRNA because of alteration of its
structure. Answer: A) continuous transcription of the structural gene
controlled by that regulator
⩥ The lactose operon is likely to be transcribed when _____.
A) there is more glucose in the cell than lactose
B) there is glucose but no lactose in the cell
C) the cyclic AMP and lactose levels are both high within the cell
D) the cAMP level is high and the lactose level is low. Answer: C) the
cyclic AMP and lactose levels are both high within the cell
⩥ Transcription of structural genes in an inducible operon _____.
A) occurs continuously in the cell
B) starts when the pathway's substrate is present
,C) starts when the pathway's product is present
D) stops when the pathway's product is present. Answer: B) starts when
the pathway's substrate is present
⩥ For a repressible operon to be transcribed, which of the following
must occur?
A) A corepressor must be present.
B) RNA polymerase and the active repressor must be present.
C) RNA polymerase must bind to the promoter, and the repressor must
be inactive.
D) RNA polymerase must not occupy the promoter, and the repressor
must be inactive.. Answer: C) RNA polymerase must bind to the
promoter, and the repressor must be inactive.
⩥ Altering patterns of gene expression in prokaryotes would most likely
serve an organism's survival by _____.
A) organizing gene expression, so that genes are expressed in a given
order
B) allowing each gene to be expressed an equal number of times
C) allowing an organism to adjust to changes in environmental
conditions
D) allowing environmental changes to alter a prokaryote's genome.
Answer: C) allowing an organism to adjust to changes in environmental
conditions
, ⩥ In positive control of several sugar-metabolism-related operons, the
catabolite activator protein (CAP) binds to DNA to stimulate
transcription. What causes an increase in CAP activity in stimulating
transcription?
A) an increase in glucose and an increase in cAMP
B) a decrease in glucose and an increase in cAMP
C) an increase in glucose and a decrease in cAMP
D) a decrease in glucose and a decrease in the repressor. Answer: B) a
decrease in glucose and an increase in cAMP
⩥ There is a mutation in the repressor that results in a molecule known
as a super-repressor because it represses the lac operon permanently.
Which of these would characterize such a mutant?
A) It cannot bind to the operator.
B) It cannot make a functional repressor.
C) It cannot bind to the inducer.
D) It makes a repressor that binds CAP.. Answer: C) It cannot bind to the
inducer.
⩥ If she moves the promoter for the lac operon to the region between the
beta galactosidase (lacZ) gene and the permease (lacY) gene, which of
the following would be likely?
A) The three structural genes will be expressed normally.
B) RNA polymerase will no longer transcribe permease.
COMPREHENSIVE EXAM 2026 STUDY
GUIDE Q&A UPDATED
⩥ A lack of which molecule would result in a cell's inability to "turn off"
genes?
A) operon
B) inducer
C) promoter
D) corepressor. Answer: D) corepressor
⩥ Which of the following, when taken up by a cell, binds to a repressor
so that the repressor no longer binds to the operator?
A) inducer
B) promoter
C) repressor
D) corepressor. Answer: A) inducer
⩥ Most repressor proteins are allosteric. Which of the following binds
with the repressor to alter its conformation?
A) inducer
B) promoter
,C) transcription factor
D) cAMP. Answer: A) inducer
⩥ A mutation that inactivates a regulatory gene of a repressible operon
in an E. coli cell would result in _____.
A) continuous transcription of the structural gene controlled by that
regulator
B) complete inhibition of transcription of the structural gene controlled
by that regulator
C) irreversible binding of the repressor to the operator
D) continuous translation of the mRNA because of alteration of its
structure. Answer: A) continuous transcription of the structural gene
controlled by that regulator
⩥ The lactose operon is likely to be transcribed when _____.
A) there is more glucose in the cell than lactose
B) there is glucose but no lactose in the cell
C) the cyclic AMP and lactose levels are both high within the cell
D) the cAMP level is high and the lactose level is low. Answer: C) the
cyclic AMP and lactose levels are both high within the cell
⩥ Transcription of structural genes in an inducible operon _____.
A) occurs continuously in the cell
B) starts when the pathway's substrate is present
,C) starts when the pathway's product is present
D) stops when the pathway's product is present. Answer: B) starts when
the pathway's substrate is present
⩥ For a repressible operon to be transcribed, which of the following
must occur?
A) A corepressor must be present.
B) RNA polymerase and the active repressor must be present.
C) RNA polymerase must bind to the promoter, and the repressor must
be inactive.
D) RNA polymerase must not occupy the promoter, and the repressor
must be inactive.. Answer: C) RNA polymerase must bind to the
promoter, and the repressor must be inactive.
⩥ Altering patterns of gene expression in prokaryotes would most likely
serve an organism's survival by _____.
A) organizing gene expression, so that genes are expressed in a given
order
B) allowing each gene to be expressed an equal number of times
C) allowing an organism to adjust to changes in environmental
conditions
D) allowing environmental changes to alter a prokaryote's genome.
Answer: C) allowing an organism to adjust to changes in environmental
conditions
, ⩥ In positive control of several sugar-metabolism-related operons, the
catabolite activator protein (CAP) binds to DNA to stimulate
transcription. What causes an increase in CAP activity in stimulating
transcription?
A) an increase in glucose and an increase in cAMP
B) a decrease in glucose and an increase in cAMP
C) an increase in glucose and a decrease in cAMP
D) a decrease in glucose and a decrease in the repressor. Answer: B) a
decrease in glucose and an increase in cAMP
⩥ There is a mutation in the repressor that results in a molecule known
as a super-repressor because it represses the lac operon permanently.
Which of these would characterize such a mutant?
A) It cannot bind to the operator.
B) It cannot make a functional repressor.
C) It cannot bind to the inducer.
D) It makes a repressor that binds CAP.. Answer: C) It cannot bind to the
inducer.
⩥ If she moves the promoter for the lac operon to the region between the
beta galactosidase (lacZ) gene and the permease (lacY) gene, which of
the following would be likely?
A) The three structural genes will be expressed normally.
B) RNA polymerase will no longer transcribe permease.
