Question 1

Which of the following is necessary for negative control of the tryptophan operon?

Accepted Answer

A)  leader sequence 
B)  operator 
C)  promoter 
D)  all of the above 
A)  leader sequence 
B)  operator 
C)  promoter 
D)  all of the above D

Question 2

Cyclic AMP is synthesized from ATP by an enzyme called

Accepted Answer

A)  catabolite activator protein (CAP) activase. 
B)  RNA polymerase. 
C)  adenylate cyclase. 
D)  cAMP receptor protein (CRP) receptase. 
A)  catabolite activator protein (CAP) activase. 
B)  RNA polymerase. 
C)  adenylate cyclase. 
D)  cAMP receptor protein (CRP) receptase. C

Question 3

Explain the sequence of events that would follow the transfer of an organism from a complex medium to a minimal medium.

Accepted Answer

Answers will vary but should include the overall need for an increased number of genes to be turned on, which were not necessary in a complex medium. For example, tRNA synthetases for amino acids would need to be made if the minimal medium did not contain sufficient quantities of each amino acid required during translation of peptides.

Question 4

Arginine in the culture medium

Accepted Answer

A)  has no effect on the enzymes required for the production of arginine. 
B)  enhances the synthesis of the enzymes required for the production of arginine. 
C)  neutralizes the enzymes required for the production of arginine. 
D)  represses the synthesis of the enzymes required for the production of arginine. 
A)  has no effect on the enzymes required for the production of arginine. 
B)  enhances the synthesis of the enzymes required for the production of arginine. 
C)  neutralizes the enzymes required for the production of arginine. 
D)  represses the synthesis of the enzymes required for the production of arginine.

Question 5

Explain why cellular cannibalism is beneficial for sporulating Bacillus subtilis.

Accepted Answer

A cell that undergoes sporulation in res

Question 6

________are RNA molecules that resemble repressors and activators in binding metabolites and regulating gene expression.

Accepted Answer

The answer of ________are RNA molecules that resemble repressors and...

Question 7

Explain why one cell of a pathogenic bacterium by itself typically does not secrete a toxin, despite the species as a whole being characterized as toxin producing.

Accepted Answer

One pathogenic bacterium is unlikely to

Question 8

The catabolism of the sugar maltose in Escherichia coli is an example of a system that involves positive regulation.

Accepted Answer

A) True 
 B)False

Question 9

Describe the basic two- component regulatory system.

Accepted Answer

The first component of the system involv

Question 10

What is the direct cause of catabolite repression?

Accepted Answer

A)  the synthesis of fi- galactosidase 
B)  the presence of glucose and lactose in a growth medium 
C)  binding of CAP to the DNA 
D)  a cellular deficiency of cyclic AMP 
A)  the synthesis of fi- galactosidase 
B)  the presence of glucose and lactose in a growth medium 
C)  binding of CAP to the DNA 
D)  a cellular deficiency of cyclic AMP

Question 11

Heat shock proteins perform which of the following functions?

Accepted Answer

A)  prevent aggregation of newly synthesized proteins 
B)  remove denatured or irreversibly aggregated proteins 
C)  catalyze the correct folding of misfolded proteins 
D)  all of the above 
A)  prevent aggregation of newly synthesized proteins 
B)  remove denatured or irreversibly aggregated proteins 
C)  catalyze the correct folding of misfolded proteins 
D)  all of the above

Question 12

Provide evidence that supports the hypothesis that riboswitches are remnants of the RNA world when catalytic RNAs were the only self- replicating life forms.

Accepted Answer

The answer of Provide evidence that supports the hypothesis that...

Question 13

In the tryptophan operon, translation of the leader peptide regulates transcription of the tryptophan genes downstream and is called attenuation.

Accepted Answer

A) True 
 B)False

Question 14

In negative control of transcription, how does the presence of an inducer affect transcription?

Accepted Answer

A)  The inducer does not bind to the operator. 
B)  The inducer binds to the operator. 
C)  The inducer causes the repressor to bind to the operator. 
D)  The inducer prevents the repressor from binding to the operator. 
A)  The inducer does not bind to the operator. 
B)  The inducer binds to the operator. 
C)  The inducer causes the repressor to bind to the operator. 
D)  The inducer prevents the repressor from binding to the operator.

Question 15

Most DNA- binding proteins interact with DNA in a sequence- specific manner.

Accepted Answer

A) True 
 B)False

Question 16

Explain why regulation of enzyme synthesis is more time consuming than regulation of enzymatic activity.

Accepted Answer

Regulating enzyme synthesis requires eit

Question 17

In most cases, the first product of a particular biosynthetic pathway represses the enzymes of the pathway.

Accepted Answer

A) True 
 B)False

Question 18

The regulation of enzyme synthesis is usually a more rapid process than the regulation of enzyme activity.

Accepted Answer

A) True 
 B)False

Question 19

Explain the translational attenuation mechanism.

Accepted Answer

Attenuation is a mechanism that controls

Question 20

Enzyme repression and induction occur at the level of

Accepted Answer

A)  translation. 
B)  pretranscription. 
C)  transcription. 
D)  posttranslation. 
A)  translation. 
B)  pretranscription. 
C)  transcription. 
D)  posttranslation.

Exam 8: Regulation of Gene Expression

Which of the following is necessary for negative control of the tryptophan operon?

Cyclic AMP is synthesized from ATP by an enzyme called

Explain the sequence of events that would follow the transfer of an organism from a complex medium to a minimal medium.

Arginine in the culture medium

Explain why cellular cannibalism is beneficial for sporulating Bacillus subtilis.

________are RNA molecules that resemble repressors and activators in binding metabolites and regulating gene expression.

Explain why one cell of a pathogenic bacterium by itself typically does not secrete a toxin, despite the species as a whole being characterized as toxin producing.

The catabolism of the sugar maltose in Escherichia coli is an example of a system that involves positive regulation.

Describe the basic two- component regulatory system.

What is the direct cause of catabolite repression?

Heat shock proteins perform which of the following functions?

Provide evidence that supports the hypothesis that riboswitches are remnants of the RNA world when catalytic RNAs were the only self- replicating life forms.

In the tryptophan operon, translation of the leader peptide regulates transcription of the tryptophan genes downstream and is called attenuation.

In negative control of transcription, how does the presence of an inducer affect transcription?

Most DNA- binding proteins interact with DNA in a sequence- specific manner.

Explain why regulation of enzyme synthesis is more time consuming than regulation of enzymatic activity.

In most cases, the first product of a particular biosynthetic pathway represses the enzymes of the pathway.

The regulation of enzyme synthesis is usually a more rapid process than the regulation of enzyme activity.

Explain the translational attenuation mechanism.

Enzyme repression and induction occur at the level of

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