BIO 340 Exam 3
Questions and
Complete Solutions
Graded A+
Denning [Date] [Course title]
, What will be the effect on transcription when an INHIBITOR is in play - Correct Ans: Reduce
transcription
What will be the effect on transcription when an INDUCER is in play - Correct Ans: Allow transcription
For a gene under positive control, what would reduce transcription - Correct Ans: Inhibitor
For a gene under negative control what would you expect to find bound to the repressor if there is
active transcription - Correct Ans: Inducer
Which molecule serves as an inducer for the lac operon - Correct Ans: Allolactose
What conditions will result in the greatest levels of transcription of the lac operon - Correct Ans: lactose
present, glucose absent
What mutation will result in the lowest level of transcription of the lac operon when lactose is present -
Correct Ans: a mutation in the lac repressor that prevents it from binding allolactose
The expression of a gene can be increased by - Correct Ans: knocking out its repressor
A bacterium is unable to transport lactose into the cell to be broken down. Which gene is likely mutated
in this bacterium? - Correct Ans: lacY
Under what conditions will E.coli make the least amount of B-galactosidase - Correct Ans: I^sO^+Z^+,
glucose absent, lactose present
In terms of lac operon regulation, what happens when an I+,O+,P+,Z- mutant E. coli is grown in medium
containing very low glucose and high lactose? - Correct Ans: Both CAP and lac repressor are bound to
DNA, E.coli does not grow.
Which of the following tends to loosen the interaction between DNA and histones?
A.) acetylation of histone tails
Questions and
Complete Solutions
Graded A+
Denning [Date] [Course title]
, What will be the effect on transcription when an INHIBITOR is in play - Correct Ans: Reduce
transcription
What will be the effect on transcription when an INDUCER is in play - Correct Ans: Allow transcription
For a gene under positive control, what would reduce transcription - Correct Ans: Inhibitor
For a gene under negative control what would you expect to find bound to the repressor if there is
active transcription - Correct Ans: Inducer
Which molecule serves as an inducer for the lac operon - Correct Ans: Allolactose
What conditions will result in the greatest levels of transcription of the lac operon - Correct Ans: lactose
present, glucose absent
What mutation will result in the lowest level of transcription of the lac operon when lactose is present -
Correct Ans: a mutation in the lac repressor that prevents it from binding allolactose
The expression of a gene can be increased by - Correct Ans: knocking out its repressor
A bacterium is unable to transport lactose into the cell to be broken down. Which gene is likely mutated
in this bacterium? - Correct Ans: lacY
Under what conditions will E.coli make the least amount of B-galactosidase - Correct Ans: I^sO^+Z^+,
glucose absent, lactose present
In terms of lac operon regulation, what happens when an I+,O+,P+,Z- mutant E. coli is grown in medium
containing very low glucose and high lactose? - Correct Ans: Both CAP and lac repressor are bound to
DNA, E.coli does not grow.
Which of the following tends to loosen the interaction between DNA and histones?
A.) acetylation of histone tails
