Question 1

Based on DNA hybridization, humans and chimpanzees are the same species.

Accepted Answer

A) True 
 B)False

Question 2

You have isolated a bacterium from a contaminated river but you are unable to culture it in the laboratory. Which method could you use to identify the organism?

Accepted Answer

A)  Gram staining 
B)  Biochemical testing 
C)  MALDI-TOF mass spectrometry 
D)  Nucleic acid amplification tests 
E)  Antibiograms 
A)  Gram staining 
B)  Biochemical testing 
C)  MALDI-TOF mass spectrometry 
D)  Nucleic acid amplification tests 
E)  Antibiograms

Question 3

Size and shape may allow one to differentiate between a bacterium, fungus, and protozoan.

Accepted Answer

A) True 
 B)False

Question 4

Your patient asks what other types of tests are available for identifying N. gonorrhoeae. You tell him that the organism is fastidious, oxidizes only glucose as a carbohydrate source, breaks down H2O2, exhibits cytochrome c oxidase activity, is resistant to the antibiotic colistin, and produces at least four different colony types. Based on this, which of the following would you NOT use for characterization of this pathogen?

Accepted Answer

A)  Colony morphology 
B)  Oxidase test 
C)  Ability to utilize different carbohydrates 
D)  Catalase test 
E)  Growth on selective medium 
A)  Colony morphology 
B)  Oxidase test 
C)  Ability to utilize different carbohydrates 
D)  Catalase test 
E)  Growth on selective medium

Question 5

In the 1930s Kluyver and van Niel proposed a classification scheme based on

Accepted Answer

A)  Gram reactions. 
B)  biochemical relationships. 
C)  DNA sequences. 
D)  presumed evolutionary relationships. 
E)  cell wall. 
A)  Gram reactions. 
B)  biochemical relationships. 
C)  DNA sequences. 
D)  presumed evolutionary relationships. 
E)  cell wall.

Question 6

If the GC content of two organisms is 45% in both,

Accepted Answer

A)  they are definitely related. 
B)  they are definitely not related. 
C)  they may or may not be related. 
D)  the AT content is 65%. 
E)  they are definitely related AND the AT content is 65%. 
A)  they are definitely related. 
B)  they are definitely not related. 
C)  they may or may not be related. 
D)  the AT content is 65%. 
E)  they are definitely related AND the AT content is 65%.

Question 7

Streptococcus pyogenes would be

Accepted Answer

A)  beta hemolytic AND catalase negative. 
B)  beta hemolytic AND catalase positive. 
C)  alpha hemolytic AND catalase negative. 
D)  alpha hemolytic AND catalase positive. 
E)  gamma hemolytic AND catalase neutral. 
A)  beta hemolytic AND catalase negative. 
B)  beta hemolytic AND catalase positive. 
C)  alpha hemolytic AND catalase negative. 
D)  alpha hemolytic AND catalase positive. 
E)  gamma hemolytic AND catalase neutral.

Question 8

Woese

Accepted Answer

A)  was involved in determining rRNA sequences AND proposed breaking prokaryotes into two groups. 
B)  was involved in determining rRNA sequences AND proposed breaking eukaryotes into domains Archaea and Bacteria. 
C)  proposed breaking prokaryotes into two groups AND was involved in refining the Gram stain for classification purposes. 
D)  proposed breaking eukaryotes into domains Archaea and Bacteria AND was involved in refining the Gram stain for classification purposes. 
E)  was involved in determining DNA sequences AND proposed breaking eukaryotes into domains Archaea and Bacteria. 
A)  was involved in determining rRNA sequences AND proposed breaking prokaryotes into two groups. 
B)  was involved in determining rRNA sequences AND proposed breaking eukaryotes into domains Archaea and Bacteria. 
C)  proposed breaking prokaryotes into two groups AND was involved in refining the Gram stain for classification purposes. 
D)  proposed breaking eukaryotes into domains Archaea and Bacteria AND was involved in refining the Gram stain for classification purposes. 
E)  was involved in determining DNA sequences AND proposed breaking eukaryotes into domains Archaea and Bacteria.

Question 9

Phage typing

Accepted Answer

A)  is useful for determining eukaryotic cell types. 
B)  is used to extract DNA from cells. 
C)  is used to distinguish bacterial strains. 
D)  is dependent on the type of eukaryotic cell. 
E)  is used to distinguish bacterial strains AND is dependent on the type of eukaryotic cell. 
A)  is useful for determining eukaryotic cell types. 
B)  is used to extract DNA from cells. 
C)  is used to distinguish bacterial strains. 
D)  is dependent on the type of eukaryotic cell. 
E)  is used to distinguish bacterial strains AND is dependent on the type of eukaryotic cell.

Question 10

If the GC content of two organisms is 60%, the

Accepted Answer

A)  organisms are most likely related. 
B)  organisms are definitely not related. 
C)  organisms will have identical RFLP profiles. 
D)  organisms are probably both pathogens. 
E)  AT content is 60%. 
A)  organisms are most likely related. 
B)  organisms are definitely not related. 
C)  organisms will have identical RFLP profiles. 
D)  organisms are probably both pathogens. 
E)  AT content is 60%.

Question 11

Horizontal DNA transfer may make it more difficult to construct phylogenetic trees.

Accepted Answer

A) True 
 B)False

Question 12

rRNA sequence comparisons are useful for determining evolutionary relationships.

Accepted Answer

A) True 
 B)False

Question 13

The reference for taxonomic descriptions of bacteria is

Accepted Answer

A)  Gray's Anatomy. 
B)  Websters Manual of Taxonomic Bacteriology. 
C)  Bergey's Manual of Systematic Bacteriology. 
D)  Big Book of Bacteriology. 
E)  Oxford Book of Bacterial Classification. 
A)  Gray's Anatomy. 
B)  Websters Manual of Taxonomic Bacteriology. 
C)  Bergey's Manual of Systematic Bacteriology. 
D)  Big Book of Bacteriology. 
E)  Oxford Book of Bacterial Classification.

Question 14

Two isolates with identical RFLPs are considered

Accepted Answer

A)  definitely the same strain. 
B)  different strains. 
C)  possibly the same strain. 
D)  different genera. 
E)  identical. 
A)  definitely the same strain. 
B)  different strains. 
C)  possibly the same strain. 
D)  different genera. 
E)  identical.

Question 15

Please select the FALSE definition regarding microbial identification.

Accepted Answer

A)  A biotype is a group of strains that have a characteristic biochemical pattern different from other strains. 
B)  A serovar is a group of strains that have a characteristic antigenic structure that differs from other strains. 
C)  A species is a group of closely related strains; it is the basic unit of taxonomy. 
D)  RFLPs are patterns of fragment sizes obtained by digesting polypeptides with one or more proteases. 
E)  A signature sequence is a nucleotide sequence in rRNA that characterizes a certain species or a group of related organisms. 
A)  A biotype is a group of strains that have a characteristic biochemical pattern different from other strains. 
B)  A serovar is a group of strains that have a characteristic antigenic structure that differs from other strains. 
C)  A species is a group of closely related strains; it is the basic unit of taxonomy. 
D)  RFLPs are patterns of fragment sizes obtained by digesting polypeptides with one or more proteases. 
E)  A signature sequence is a nucleotide sequence in rRNA that characterizes a certain species or a group of related organisms.

Question 16

Disagreements between conclusions obtained from rRNA data and other techniques may be explained by

Accepted Answer

A)  horizontal DNA transfer. 
B)  vertical DNA transfer. 
C)  the difference in translation machinery. 
D)  vertical RNA transfer. 
E)  differences in post-replication modification. 
A)  horizontal DNA transfer. 
B)  vertical DNA transfer. 
C)  the difference in translation machinery. 
D)  vertical RNA transfer. 
E)  differences in post-replication modification.

Question 17

Despite the fact that you are certain that your patient has gonorrhea based on the Gram stain results, it is essential to confirm your diagnosis by 16S rRNA sequencing.

Accepted Answer

A) True 
 B)False

Question 18

A probe is a single-stranded piece of nucleic acid labeled with a detectable marker, used to locate a unique nucleotide sequence that identifies a particular microbial species.

Accepted Answer

A) True 
 B)False

Question 19

Which type of ribosomal RNA is most often used in taxonomy?

Accepted Answer

A)  5S 
B)  23S 
C)  70S 
D)  80S 
E)  16S 
A)  5S 
B)  23S 
C)  70S 
D)  80S 
E)  16S

Question 20

Why might it be easier to identify the bacterium that caused pneumonia than one that caused a wound infection?

Accepted Answer

A)  There are very few microorganisms that can cause pneumonia, while there are many that can cause wound infections, including normal microbiota and a variety of environmental organisms. 
B)  Bacteria that cause pneumonia can be identified with few tests because the lungs have no normal microbiota. Many bacteria are normally found on the skin however; these may be in the wound, complicating identification. 
C)  We have much better tests for bacteria in the lungs than we do for bacteria on the skin which may be the causative agents of wounds infection. 
D)  The techniques of 16S rRNA sequencing are easier to perform on a sample taken from the lungs than a sample taken from a wound, because it is easier to get a sputum sample than it is a wound sample. 
E)  Very few people actually get pneumonia, so tests are quick and easy to carry out; on the other hand, many people get very serious wound infections, so the tests are more complicated. 
A)  There are very few microorganisms that can cause pneumonia, while there are many that can cause wound infections, including normal microbiota and a variety of environmental organisms. 
B)  Bacteria that cause pneumonia can be identified with few tests because the lungs have no normal microbiota. Many bacteria are normally found on the skin however; these may be in the wound, complicating identification. 
C)  We have much better tests for bacteria in the lungs than we do for bacteria on the skin which may be the causative agents of wounds infection. 
D)  The techniques of 16S rRNA sequencing are easier to perform on a sample taken from the lungs than a sample taken from a wound, because it is easier to get a sputum sample than it is a wound sample. 
E)  Very few people actually get pneumonia, so tests are quick and easy to carry out; on the other hand, many people get very serious wound infections, so the tests are more complicated.

Exam 10: Identifying and Classifying Microorganisms

Based on DNA hybridization, humans and chimpanzees are the same species.

You have isolated a bacterium from a contaminated river but you are unable to culture it in the laboratory. Which method could you use to identify the organism?

Size and shape may allow one to differentiate between a bacterium, fungus, and protozoan.

In the 1930s Kluyver and van Niel proposed a classification scheme based on

If the GC content of two organisms is 45% in both,

Streptococcus pyogenes would be

Woese

Phage typing

If the GC content of two organisms is 60%, the

Horizontal DNA transfer may make it more difficult to construct phylogenetic trees.

rRNA sequence comparisons are useful for determining evolutionary relationships.

The reference for taxonomic descriptions of bacteria is

Two isolates with identical RFLPs are considered

Please select the FALSE definition regarding microbial identification.

Disagreements between conclusions obtained from rRNA data and other techniques may be explained by

Despite the fact that you are certain that your patient has gonorrhea based on the Gram stain results, it is essential to confirm your diagnosis by 16S rRNA sequencing.

A probe is a single-stranded piece of nucleic acid labeled with a detectable marker, used to locate a unique nucleotide sequence that identifies a particular microbial species.

Which type of ribosomal RNA is most often used in taxonomy?

Why might it be easier to identify the bacterium that caused pneumonia than one that caused a wound infection?

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, From Dna to Protein

Bacterial Genetics

Biotechnology

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

Viruses, Viroids, and Prions

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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