Question 1

Mobile resistance genes encode enzymes that inactivate an antibiotic by altering its structure.

Accepted Answer

A) True 
 B)False  TRUE

Question 2

What role does the Par system play in bacterial cell division?

Accepted Answer

The Par (partitioning) system can be found in many bacteria including Caulobacter which undergoes budding. Similar to mitotic spindle fibers which separate replicated chromosomes in eukaryotic cells, the Par system distributes chromosomes and plasmids equally to progeny cells during growth. This system is composed of the ParAATPase, the ParB chromosome-binding protein, and the PopZ complex, as well as a centromere-like parS sequence located near oriC.

Question 3

FtsZ is related to ________, an important protein involved in cell division.

Accepted Answer

A)  actin 
B)  myosin 
C)  tubulin 
D)  collagen 
A)  actin 
B)  myosin 
C)  tubulin 
D)  collagen C

Question 4

What is the function of bactoprenol?

Accepted Answer

A)  It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane. 
B)  It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains. 
C)  It triggers the recruitment of FtsZ and the initiation of the divisome. 
D)  It supplies the energy necessary for transpeptidation to occur. 
A)  It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane. 
B)  It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains. 
C)  It triggers the recruitment of FtsZ and the initiation of the divisome. 
D)  It supplies the energy necessary for transpeptidation to occur.

Question 5

Which of the following activities is a result of cyclic di-guanosine monophosphate synthesis?

Accepted Answer

A)  transition from planktonic to sessile growth during biofilm formation 
B)  reduction in activity of flagellar motor 
C)  biosynthesis of extracellular matrix during biofilm formation 
D)  All of these answer choices activities are a result of cyclic di-guanosine monophosphate synthesis. 
A)  transition from planktonic to sessile growth during biofilm formation 
B)  reduction in activity of flagellar motor 
C)  biosynthesis of extracellular matrix during biofilm formation 
D)  All of these answer choices activities are a result of cyclic di-guanosine monophosphate synthesis.

Question 6

The Par system is necessary for

Accepted Answer

A)  formation of a replication fork in Escherichia coli. 
B)  distribution of genetic material in replicating Caulobacter. 
C)  septum formation. 
D)  elongation of bacillus prior to cell division. 
A)  formation of a replication fork in Escherichia coli. 
B)  distribution of genetic material in replicating Caulobacter. 
C)  septum formation. 
D)  elongation of bacillus prior to cell division.

Question 7

Endospore formation is stimulated when

Accepted Answer

A)  bacterial growth ceases due to limitation of an essential nutrient. 
B)  the bacterium is undergoing binary fission. 
C)  bacteria are dividing exponentially. 
D)  nutrient levels rise. 
A)  bacterial growth ceases due to limitation of an essential nutrient. 
B)  the bacterium is undergoing binary fission. 
C)  bacteria are dividing exponentially. 
D)  nutrient levels rise.

Question 8

Nitrogen fixation utilizes the enzyme nitrogenase, which is extremely sensitive to oxygen. How do cyanobacteria carry on both oxygenic photosynthesis and nitrogen fixation at the same time?

Accepted Answer

Some filamentous cyanobacteria such as A

Question 9

Penicillins work by

Accepted Answer

A)  activating autolytic enzymes. 
B)  blocking the transpeptidation reaction that forms peptidoglycan cross-links. 
C)  stimulating autolysins to form holes in the plasma membrane. 
D)  All of these answer choices are true. 
A)  activating autolytic enzymes. 
B)  blocking the transpeptidation reaction that forms peptidoglycan cross-links. 
C)  stimulating autolysins to form holes in the plasma membrane. 
D)  All of these answer choices are true.

Question 10

Shortage of key nutrients such as ________ results in transcription and secretion of a toxic protein that leads to cannibalization of neighboring cells of the same species.

Accepted Answer

A)  magnesium 
B)  phosphate 
C)  calcium 
D)  iron 
A)  magnesium 
B)  phosphate 
C)  calcium 
D)  iron

Question 11

The typical generation time of Escherichia coli is approximately ________ under optimal environmental conditions.

Accepted Answer

A)  10 minutes 
B)  20 minutes 
C)  30 minutes 
D)  40 minutes 
A)  10 minutes 
B)  20 minutes 
C)  30 minutes 
D)  40 minutes

Question 12

The curved-rod shape typical of Caulobacter is due to the protein(s)

Accepted Answer

A)  crescentin. 
B)  MreB. 
C)  crescentin and MreB. 
D)  neither crescentin nor MreB. 
A)  crescentin. 
B)  MreB. 
C)  crescentin and MreB. 
D)  neither crescentin nor MreB.

Question 13

All of the following are targets of currently used antibiotics EXCEPT

Accepted Answer

A)  DNA synthesis. 
B)  biofilm formation. 
C)  transcription. 
D)  translation. 
A)  DNA synthesis. 
B)  biofilm formation. 
C)  transcription. 
D)  translation.

Question 14

The typical time required for chromosome replication in Escherichia coli is

Accepted Answer

A)  10 minutes. 
B)  20 minutes. 
C)  30 minutes. 
D)  40 minutes. 
A)  10 minutes. 
B)  20 minutes. 
C)  30 minutes. 
D)  40 minutes.

Question 15

Fluorescence microscopy allows visualization of all of the following EXCEPT

Accepted Answer

A)  cytoskeletal proteins. 
B)  nuclear proteins. 
C)  interactions between cytoplasmic proteins. 
D)  All of these answer choices can be visualized. 
A)  cytoskeletal proteins. 
B)  nuclear proteins. 
C)  interactions between cytoplasmic proteins. 
D)  All of these answer choices can be visualized.

Question 16

Prior to DNA replication, both strands of the chromosome are methylated on the ________ residue of the sequence-GATC-.

Accepted Answer

A)  A 
B)  G 
C)  C 
D)  T 
A)  A 
B)  G 
C)  C 
D)  T

Question 17

The chemical composition of the peptidoglycan carrier bactoprenol is highly hydrophobic. Explain why this is necessary for bactroprenol to carry on its function.

Accepted Answer

Bactoprenol is a hydrophobic C55 alcohol

Question 18

Why is the presence of a cell wall significant from a clinical standpoint?

Accepted Answer

A)  All types of cells have a cell wall, and it makes identification of the causative agent of disease difficult. 
B)  The cell wall protects microorganisms from destruction by the immune system. 
C)  Animal cells do not have cell walls, so antibiotics that target cell walls can selectively destroy invading microorganisms. 
D)  Only gram-negative Bacteria have cell walls. 
A)  All types of cells have a cell wall, and it makes identification of the causative agent of disease difficult. 
B)  The cell wall protects microorganisms from destruction by the immune system. 
C)  Animal cells do not have cell walls, so antibiotics that target cell walls can selectively destroy invading microorganisms. 
D)  Only gram-negative Bacteria have cell walls.

Question 19

Quorum sensing generally follows the mechanism of which type of regulation?

Accepted Answer

A)  feedback inhibition 
B)  negative transcriptional regulation 
C)  positive transcriptional regulation 
D)  a two-component regulation system 
A)  feedback inhibition 
B)  negative transcriptional regulation 
C)  positive transcriptional regulation 
D)  a two-component regulation system

Question 20

Explain why the antibiotic penicillin is effective at destroying bacteria but does not have a similar effect in eukaryotic cells.

Accepted Answer

Animal cells do not possess a cell wall

Exam 7: Molecular Biology of Microbial Growth

Mobile resistance genes encode enzymes that inactivate an antibiotic by altering its structure.

What role does the Par system play in bacterial cell division?

FtsZ is related to ________, an important protein involved in cell division.

What is the function of bactoprenol?

Which of the following activities is a result of cyclic di-guanosine monophosphate synthesis?

The Par system is necessary for

Endospore formation is stimulated when

Nitrogen fixation utilizes the enzyme nitrogenase, which is extremely sensitive to oxygen. How do cyanobacteria carry on both oxygenic photosynthesis and nitrogen fixation at the same time?

Penicillins work by

Shortage of key nutrients such as ________ results in transcription and secretion of a toxic protein that leads to cannibalization of neighboring cells of the same species.

The typical generation time of Escherichia coli is approximately ________ under optimal environmental conditions.

The curved-rod shape typical of Caulobacter is due to the protein(s)

All of the following are targets of currently used antibiotics EXCEPT

The typical time required for chromosome replication in Escherichia coli is

Fluorescence microscopy allows visualization of all of the following EXCEPT

Prior to DNA replication, both strands of the chromosome are methylated on the ________ residue of the sequence-GATC-.

The chemical composition of the peptidoglycan carrier bactoprenol is highly hydrophobic. Explain why this is necessary for bactroprenol to carry on its function.

Why is the presence of a cell wall significant from a clinical standpoint?

Quorum sensing generally follows the mechanism of which type of regulation?

Explain why the antibiotic penicillin is effective at destroying bacteria but does not have a similar effect in eukaryotic cells.

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Microbial Cell Structure and Function

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Molecular Information Flow and Protein Processing

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Genetics of Bacteria and Archaea

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Diversity of Microbial Eukarya

Taking the Measure of Microbial Systems

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Microbial Infection and Pathogenesis

Innate Immunity: Broadly Specific Host Defenses

Adaptive Immunity: Highly Specific Host Defenses

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