Question 1

How is the leucine zipper formed,and what is its function?

Accepted Answer

The leucine zipper is a specific domain,

Question 2

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,especiall

Question 3

Interpret the results to the following experiment.Transcriptional activity of chemotactic genes showed a high expression level during the following conditions: repelling away from compound 1,moving towards compound 2,and remaining sessile when presented compounds 3 and 4.

Accepted Answer

A)  Activity during movement in any direction led to high measurements observed, and the sessile population responded equally to both a chemoattractant and a chemorepellant but remained in the same location for their net movement. 
B)  Gene expression by itself cannot distinguish between cells responding to both an attractant and repellent, so this ambiguity makes transcriptomics unfavorable but nonetheless indicates activity. 
C)  The activity observed during a sessile existence suggests the molecular probe was targeting a chemotactic gene that is also involved in other non-chemotactic functions due to the activity observed. 
D)  Transcriptomics as a whole cannot be used for chemotaxis genes because they are not regulated at the transcriptional level (i.e., they are constitutive), which is why activity is observed on all three conditions. 
A)  Activity during movement in any direction led to high measurements observed, and the sessile population responded equally to both a chemoattractant and a chemorepellant but remained in the same location for their net movement. 
B)  Gene expression by itself cannot distinguish between cells responding to both an attractant and repellent, so this ambiguity makes transcriptomics unfavorable but nonetheless indicates activity. 
C)  The activity observed during a sessile existence suggests the molecular probe was targeting a chemotactic gene that is also involved in other non-chemotactic functions due to the activity observed. 
D)  Transcriptomics as a whole cannot be used for chemotaxis genes because they are not regulated at the transcriptional level (i.e., they are constitutive), which is why activity is observed on all three conditions.

Question 4

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.To help in your explanation,predict what would happen to an individual pathogen that secreted a toxin inside a human.

Accepted Answer

One pathogenic bacterium is unlikely to

Question 5

Heat shock proteins are produced at high numbers to minimize damaging effects during high heat conditions as well as other stress signals unrelated to heat such as ultraviolet radiation.

Accepted Answer

A) True 
 B)False

Question 6

What type of sRNA often requires a chaperon protein for strong regulation activity?

Accepted Answer

A)  antisense RNA 
B)  riboswitches 
C)  siRNA 
D)  trans-sRNA 
A)  antisense RNA 
B)  riboswitches 
C)  siRNA 
D)  trans-sRNA

Question 7

Based on their abundance and location in bacterial genomes,deduce which is LEAST likely to horizontally transfer into another bacterium while maintaining its identical function and regulatory roles.

Accepted Answer

A)  heat shock protein-encoding gene 
B)  lac operon 
C)  catabolic regulon 
D)  quorum sensing operon 
A)  heat shock protein-encoding gene 
B)  lac operon 
C)  catabolic regulon 
D)  quorum sensing operon

Question 8

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

Accepted Answer

Regulating enzyme synthesis requires eit

Question 9

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 10

When a Bacillus anthracis population suddenly must form spores to survive a harsh nutrient poor environment,how do the cells obtain energy?

Accepted Answer

A)  Cells in a growth phase that have not used up all of their energy will be the only ones to make endospores, which is why relatively few endospores are often made from a large population. 
B)  Intracellular energy reserves are quickly made available to produce endospores. 
C)  Slow responding cells are cannibalized by others that already began spore formation. 
D)  Global regulation is initiated to minimize energy waste in biosynthetic pathways and catabolic pathways are increased to consume remaining usable substrates to fuel spore formation. 
A)  Cells in a growth phase that have not used up all of their energy will be the only ones to make endospores, which is why relatively few endospores are often made from a large population. 
B)  Intracellular energy reserves are quickly made available to produce endospores. 
C)  Slow responding cells are cannibalized by others that already began spore formation. 
D)  Global regulation is initiated to minimize energy waste in biosynthetic pathways and catabolic pathways are increased to consume remaining usable substrates to fuel spore formation.

Question 11

Which statement is TRUE of two separate regulators controlling one individual operon?

Accepted Answer

A)  The two regulators themselves must respond to different signals, which enables both to control the operon differently. 
B)  One regulator will likely control the transcription of one section of the operon, whereas the other regulator will control the other component. 
C)  One regulator will bind to the operator region whereas the other will bind to the promoter region so they can co-occur and co-regulate the operon. 
D)  Two regulators trying to control the same operon will likely result in only one being maintained after several generations. 
A)  The two regulators themselves must respond to different signals, which enables both to control the operon differently. 
B)  One regulator will likely control the transcription of one section of the operon, whereas the other regulator will control the other component. 
C)  One regulator will bind to the operator region whereas the other will bind to the promoter region so they can co-occur and co-regulate the operon. 
D)  Two regulators trying to control the same operon will likely result in only one being maintained after several generations.

Exam 7: Metabolic Regulation

How is the leucine zipper formed,and what is its function?

Interpret the results to the following experiment.Transcriptional activity of chemotactic genes showed a high expression level during the following conditions: repelling away from compound 1,moving towards compound 2,and remaining sessile when presented compounds 3 and 4.

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.To help in your explanation,predict what would happen to an individual pathogen that secreted a toxin inside a human.

Heat shock proteins are produced at high numbers to minimize damaging effects during high heat conditions as well as other stress signals unrelated to heat such as ultraviolet radiation.

What type of sRNA often requires a chaperon protein for strong regulation activity?

Based on their abundance and location in bacterial genomes,deduce which is LEAST likely to horizontally transfer into another bacterium while maintaining its identical function and regulatory roles.

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

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

When a Bacillus anthracis population suddenly must form spores to survive a harsh nutrient poor environment,how do the cells obtain energy?

Which statement is TRUE of two separate regulators controlling one individual operon?

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