Question 1

Global regulatory systems include all of the following EXCEPT

Accepted Answer

A)  amino acid synthesis. 
B)  transformation. 
C)  heat shock response. 
D)  anaerobic respiration. 
A)  amino acid synthesis. 
B)  transformation. 
C)  heat shock response. 
D)  anaerobic respiration.

Question 2

When environmental levels of amino acids become limited, synthesis of mRNA, rRNA, and tRNA increases immediately.

Accepted Answer

A) True 
 B)False

Question 3

Quorum sensing relies upon a large cell population which then turns on transcription.

Accepted Answer

A) True 
 B)False

Question 4

Explain a common mechanism used by cells to ensure proper binding of DNA-binding proteins to DNA.

Accepted Answer

DNA-binding proteins are proteins compos

Question 5

Compare and contrast chemical, spatial, and temporal gradients as found in bacterial regulatory systems.

Accepted Answer

Bacteria cannot sense spatial gradients

Question 6

A regulon is composed of at least two operons regulated by the same protein.

Accepted Answer

A) True 
 B)False

Question 7

The most frequent way in which small regulatory RNA molecules exert their effects is by

Accepted Answer

A)  base pairing with other RNA molecules that have regions of complementary sequence. 
B)  binding to a repressor and repressing enzyme transcription. 
C)  acting as an inducer that then binds to an activator protein to allow transcription to proceed. 
D)  signal transduction. 
A)  base pairing with other RNA molecules that have regions of complementary sequence. 
B)  binding to a repressor and repressing enzyme transcription. 
C)  acting as an inducer that then binds to an activator protein to allow transcription to proceed. 
D)  signal transduction.

Question 8

Which regulatory mechanism does NOT depend on a conformational change in protein/enzyme structure to change activity?

Accepted Answer

A)  attenuation 
B)  catabolite repression 
C)  feedback inhibition 
D)  negative control 
A)  attenuation 
B)  catabolite repression 
C)  feedback inhibition 
D)  negative control

Question 9

Describe the difference between constitutive and inducible genes. Based on your knowledge of bacterial cells, give an example of each.

Accepted Answer

Constitutive genes are those which are t

Question 10

The stringent response is a mechanism used by bacteria that provides increased ability to survive in environments lacking nutrients.

Accepted Answer

A) True 
 B)False

Question 11

An organism grown in nutrient rich broth to high turbidity always produces a blue pigment. When a large inoculum is transferred to a nutrient rich agar plate, it also appears blue. A researcher noticed that this never happens when very small colonies are grown on low nutrient agar plates, however. What is the most plausible conclusion?

Accepted Answer

A)  Large populations enabled the differentiation of a subpopulation of cells that created the blue pigment. 
B)  Only high nutrient conditions provide enough energy for cells to produce this secondary metabolite that appears blue. 
C)  Production of the blue pigment production is linked to quorum sensing. 
D)  The strong gradient from very high to low nutrient bioavailability induces production of the blue metabolite. 
A)  Large populations enabled the differentiation of a subpopulation of cells that created the blue pigment. 
B)  Only high nutrient conditions provide enough energy for cells to produce this secondary metabolite that appears blue. 
C)  Production of the blue pigment production is linked to quorum sensing. 
D)  The strong gradient from very high to low nutrient bioavailability induces production of the blue metabolite.

Question 12

The preferential use of glucose over other available carbon substrates for growth is mechanistically explained by catabolite repression.

Accepted Answer

A) True 
 B)False

Question 13

A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will likely disrupt

Accepted Answer

A)  attenuation. 
B)  chemotaxis. 
C)  endospore formation. 
D)  quorum sensing. 
A)  attenuation. 
B)  chemotaxis. 
C)  endospore formation. 
D)  quorum sensing.

Question 14

Mechanisms for controlling enzyme activity include all of the following EXCEPT

Accepted Answer

A)  degradation of the enzyme. 
B)  feedback inhibition. 
C)  covalent modification of the enzyme. 
D)  addition of short sections of new amino acid sequence. 
A)  degradation of the enzyme. 
B)  feedback inhibition. 
C)  covalent modification of the enzyme. 
D)  addition of short sections of new amino acid sequence.

Question 15

Cyclic AMP is synthesized from ATP by an enzyme called ________ which is involved in ________.

Accepted Answer

A)  adenylate cyclase / catabolite repression 
B)  adenylate cyclase / transcriptional activation 
C)  cAMP receptor protein (CRP) synthase / catabolite repression 
D)  cAMP receptor protein (CRP) synthase / transcriptional activation 
A)  adenylate cyclase / catabolite repression 
B)  adenylate cyclase / transcriptional activation 
C)  cAMP receptor protein (CRP) synthase / catabolite repression 
D)  cAMP receptor protein (CRP) synthase / transcriptional activation

Question 16

A mutation in the gene encoding the lactose repressor (lacI) that prevents lactose from binding to the LacI protein would result in

Accepted Answer

A)  constant expression of the lac operon in the absence of lactose. 
B)  constant repression of the lac operon in the absence of lactose. 
C)  constant expression of the lac operon in the presence of lactose. 
D)  constant repression of the lac operon in the presence of lactose. 
A)  constant expression of the lac operon in the absence of lactose. 
B)  constant repression of the lac operon in the absence of lactose. 
C)  constant expression of the lac operon in the presence of lactose. 
D)  constant repression of the lac operon in the presence of lactose.

Question 17

Short regions at the beginning and end of gene sequences are not translated into proteins.

Accepted Answer

A) True 
 B)False

Question 18

A cocktail of 30 compounds was identified to harbor a corepressor, and subsequent separation and purification was performed to test individual compounds. Describe an experiment that would enable you to identify the specific compound that acts as a corepressor for a catabolic pathway. Be certain to explain what will be measured and how you could conclude which compound is a corepressor.

Accepted Answer

Experimental designs will vary, dependin

Question 19

A common structure for proteins that bind DNA is helix-turn-helix.

Accepted Answer

A) True 
 B)False

Question 20

All of the following are functions of heat shock proteins in bacteria EXCEPT

Accepted Answer

A)  prevention of inappropriate protein subunit aggregation. 
B)  degradation of denatured proteins. 
C)  responding to exposure to high levels of ethanol. 
D)  stimulation of binary fission. 
A)  prevention of inappropriate protein subunit aggregation. 
B)  degradation of denatured proteins. 
C)  responding to exposure to high levels of ethanol. 
D)  stimulation of binary fission.

Exam 6: Microbial Regulatory Systems

Global regulatory systems include all of the following EXCEPT

When environmental levels of amino acids become limited, synthesis of mRNA, rRNA, and tRNA increases immediately.

Quorum sensing relies upon a large cell population which then turns on transcription.

Explain a common mechanism used by cells to ensure proper binding of DNA-binding proteins to DNA.

Compare and contrast chemical, spatial, and temporal gradients as found in bacterial regulatory systems.

A regulon is composed of at least two operons regulated by the same protein.

The most frequent way in which small regulatory RNA molecules exert their effects is by

Which regulatory mechanism does NOT depend on a conformational change in protein/enzyme structure to change activity?

Describe the difference between constitutive and inducible genes. Based on your knowledge of bacterial cells, give an example of each.

The stringent response is a mechanism used by bacteria that provides increased ability to survive in environments lacking nutrients.

The preferential use of glucose over other available carbon substrates for growth is mechanistically explained by catabolite repression.

A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will likely disrupt

Mechanisms for controlling enzyme activity include all of the following EXCEPT

Cyclic AMP is synthesized from ATP by an enzyme called ________ which is involved in ________.

A mutation in the gene encoding the lactose repressor (lacI) that prevents lactose from binding to the LacI protein would result in

Short regions at the beginning and end of gene sequences are not translated into proteins.

A common structure for proteins that bind DNA is helix-turn-helix.

All of the following are functions of heat shock proteins in bacteria EXCEPT

The Microbial World

Microbial Cell Structure and Function

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Molecular Biology of Microbial Growth

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Cyclic AMP is synthesized from ATP by an enzyme called which is involved in .