Microbiology Ch 10 – Classification of Microorganisms

Why are archaea and bacteria—both collections of prokaryotic organisms—grouped into different domains while organisms like fungi and animals are in the same domain?

A. The DNA sequences of bacteria and archaea are more different than animals and fungi.
B. Bacteria and archaea differ significantly in their rRNA sequences, but fungi and animals share some rRNA characteristics.
C. Bacteria and archaea differ significantly in their intracellular organization and structure, but fungi and animals have similar intracellular structure.
D. Fungi and animals look much more similar than bacteria and archaea.

B. Bacteria and archaea differ significantly in their rRNA sequences, but fungi and animals share some rRNA characteristics.

While working with a broth culture of archaea in the laboratory, you accidentally spill some of the microorganisms on yourself. Do you need to be concerned about developing an infection? Why or why not?

A. No; archaea are not pathogenic.
B. Yes; certain archaea can be pathogenic, so an infection could occur.
C. No; archaea are prokaryotic, so they cannot cause infection.
D. Yes; all infectious prokaryotes are archaea.

A. No; archaea are not pathogenic.

Which of the following methods could be used to differentiate between a member of domain Bacteria and a member of domain Archaea?

A. You could look for the presence of peptidoglycan.
B. You could look for the presence of mitochondria.
C. You could see if the organism produces rRNA.
D. You could see if the organism can survive in an extreme environment.
E. All of the above would work.
F. None of the above would work.

A. You could look for the presence of peptidoglycan.

Why is visualization not sufficient to properly identify bacteria?

A. Not all bacteria can be seen with a light microscope.
B. Identification is only needed in clinical specimens.
C. Bacteria have a limited set of shapes.
D. Bacteria have a limited set of shapes and many unrelated bacteria share the same shape.
E. Many unrelated bacteria can share the same shape.

D. Bacteria have a limited set of shapes and many unrelated bacteria share the same shape.

What is the hallmark of dichotomous keys?

A. They only relate to biochemical processes of the cell.
B. They only relate to the shape of the cell.
C. They are open-ended questions.
D. They consist of a series of paired statements, in which only one statement of each pair applies to a given organism.

D. They consist of a series of paired statements, in which only one statement of each pair applies to a given organism.

Biochemical tests _________________.

A. are the main methods used to identify unknown bacteria
B. are used to determine rate of growth
C. are the most effective way to determine bacterial shape
D. are visualized using microscopes

A. are the main methods used to identify unknown bacteria

How many answers are there to a question in a dichotomous key flowchart?

Any number of answers are possible.
Two
Three
Four

Two

Why are flowcharts useful for dichotomous keys?

A. They provide a map to the answer.
B. They allow the researcher to get the answer without having to do many tests.
C. They allow the researcher to visualize relationships between different bacteria.

C. They allow the researcher to visualize relationships between different bacteria.

The first question in this dichotomous key addresses

A. metabolic characteristics.
B. oxygen tolerance.
C. bacterial morphology.
D. Gram stain differences.

D. Gram stain differences.

Why is the unknown in this example not Pseudomonas?

A. It can tolerate oxygen.
B. It ferments lactose.
C. It is a Gram-negative cell.
D. It is a rod-shaped cell.

B. It ferments lactose.

What test result indicates that the unknown can utilize citrate as its sole carbon source?

A. The medium turns blue.
B. The medium turns pink.
C. The culture becomes turbid.
D. It turns the medium black.

A. The medium turns blue.

How would the results be different if this organism was Salmonella?

A. It would produce hydrogen sulfide.
B. It would not ferment lactose.
C. It would not tolerate oxygen.
D. It would be a rod.

A. It would produce hydrogen sulfide.

How is fermentation of lactose detected?

A. The acetoin produced turns the medium pink.
B. The cells form a black precipitant.
C. The medium become turbid when exposed to air.
D. The drop in pH turns the indicator dye yellow.

D. The drop in pH turns the indicator dye yellow.

How many questions are needed in this dichotomous key to determine if the unknown is Bacteroides?

Five
Four
Two
Three

Three

How are negative stains different from other types of stains?

A. They stain the desired structure or specimen black.
B. They stain the background, leaving the cells colorless.
C. They stain more than one type of specimen.

B. They stain the background, leaving the cells colorless.

Which of the following is an example of a dye used in a simple stain?

A. Carbolfuchsin
B. Methylene blue
C. Nigrosin
D. Eosin

B. Methylene blue

How does the malachite green stain enter an endospore?

A. It is dissolved in alcohol.
B. It is mixed with the mordant tannic acid.
C. It is mixed with hydrochloric acid.
D. It is heated.

D. It is heated.

Following an endospore stain, how does one distinguish endospores from vegetative cells?

A. Vegetative cells are pink, endospores are purple.
B. Vegetative cells are pink, endospores are green.
C. Vegetative cells are green, endospores are pink.
D. Vegetative cells are purple, endospores are pink.

B. Vegetative cells are pink, endospores are green.

What is the fundamental purpose of staining in light microscopy?

A. To increase the contrast and visibility of the specimen
B. To see the specimen without the aid of a microscope
C. To kill the specimen
D. To make the specimen appear larger in the microscope

A. To increase the contrast and visibility of the specimen

Which type of organism would NOT be included in the Domain Eukarya?

A. bacterium
B. ameba
C. fungus
D. protist

A. bacterium Bacteria have a prokaryotic cell structure.

Which statement regarding viral species is true?

A. Viral species are not classified as part of any of the three domains.
B. Viral species are taxonomically differentiated based upon their cell wall.
C. Viruses are classified as prokaryotes.
D. Viral species are classified within the Kingdom Plantae in the Domain Eukarya.

A. Viral species are not classified as part of any of the three domains. Viruses are not composed of cells and cannot reproduce outside a host cell; therefore, they are not included in the three-domain system.

Which biologist introduced the term prokaryote in 1937 to distinguish cells with no nucleus from the nucleated cells of plants and animals?

A. Edouard Chatton
B. Carl von Nägeli
C. Carl Woese
D. Robert H. Whittaker

A. Edouard Chatton Edouard Chatton was a French biologist who first distinguished prokaryotic and eukaryotic cells.

Organisms once classified as protists are now being divided into which of the following?

A. clades
B. strains
C. species
D. clones

A. clades

Numerical identification methods rely on a series of which kind of test to identify microorganisms?

A. biochemical testing
B. DNA fingerprinting
C. DNA base composition
D. ELISA

A. biochemical testing

Consider a gram-negative human pathogen isolated from marine mammals. This pathogen is subjected to a series of tests and found to have the following characteristics: oxidase-positive; does not hydrolyze urea; produces indole; does not produce acetoin. Which of the following could it be?

A. Mannheimia haemolytica
B. Yersinia enterocolitica
C. Pasteurella multocida
D. Klebsiella pneumoniae

C. Pasteurella multocida

Which technique is often used to determine the identity and abundance of microorganisms in an environment? (This technique is particularly useful because it does not require culture.)

A. ribotyping
B. nucleic acid hybridization
C. DNA chips
D. fluorescent in situ hybridization (FISH)

D. fluorescent in situ hybridization (FISH) FISH is a cytogenetic technique that is used to detect specific DNA sequences.

Which test involves placing samples of an UNKNOWN bacterium in saline, adding different antisera, and checking for clumping?

A. slide agglutination
B. phage typing
C. ELISA
D. Western blotting

A. slide agglutination

Which of the following techniques could be used to identify antibodies produced by a patient?

A. FAME
B. Western blotting
C. FISH
D. Southern blotting

B. Western blotting When Western blotting is used for identification purposes, proteins from a known organism are used to determine whether a patient’s serum contains antibodies.

Which of the following characterizes the Domain Bacteria?

A. complex cellular structures
B. eukaryotic cells; ester linkages in phospholipids
C. prokaryotic cells; ether linkages in phospholipids
D. multicellular
E. prokaryotic cells; ester linkages in phospholipids

E. prokaryotic cells; ester linkages in phospholipids

Which of the following statements about Archaea is false?

A. They are prokaryotes.
B. They lack peptidoglycan in their cell walls.
C. They evolved before bacteria.
D. Some produce methane from carbon dioxide and hydrogen.
E. Some are thermoacidophiles; others are extreme halophiles.

C. They evolved before bacteria.

What is the outstanding characteristic of the Kingdom Fungi?

A. All members are photosynthetic.
B. Members absorb dissolved organic matter.
C. Members absorb dissolved inorganic matter.
D. All members are microscopic.
E. All members are macroscopic.

B. Members absorb dissolved organic matter.

Which of the following statements about members of the Kingdom Plantae is false?

A. They undergo photosynthesis.
B. They synthesize organic molecules.
C. They are composed of eukaryotic cells.
D. They use organic carbon sources.
E. They are multicellular.

D. They use organic carbon sources.

Which of the following statements about the members of the Kingdom Animalia is false?

A. They are heterotrophs.
B. They undergo photosynthesis.
C. They are composed of eukaryotic cells.
D. They ingest nutrients through a mouth.
E. They are multicellular.

B. They undergo photosynthesis.

A genus can best be defined as

A. a taxon belonging to a species.
B. a taxon composed of families.
C. a taxon comprised of classes.
D. the most specific taxon.
E. a taxon composed of one or more species and below family.

E. a taxon composed of one or more species and below family.

A bacterial species differs from a species of eukaryotic organisms in that a bacterial species

A. can be distinguished from other bacterial species.
B. is a population of cells with similar characteristics.
C. has a limited geographical distribution.
D. does not breed with other species.
E. breeds with its own species.

B. is a population of cells with similar characteristics.

Which of the following is the best evidence for a three-domain system?

A. There are three distinctly different types of nuclei.
B. Some bacteria live in extreme environments.
C. There are three distinctly different sets of metabolic reactions.
D. Nucleotide sequences in ribosomal RNA vary between all three domains.
E. There are three distinctly different Gram reactions.

D. Nucleotide sequences in ribosomal RNA vary between all three domains.

Biochemical tests are used to determine

A. nucleic acid-base composition.
B. enzymatic activities.
C. amino acid sequences.
D. staining characteristics.
E. All of the answers are correct.

B. enzymatic activities.

The phylogenetic classification of bacteria is based on

A. cell morphology.
B. diseases.
C. rRNA sequences.
D. gram reaction.
E. habitat.

C. rRNA sequences.

Which of the following statements is a reason for NOT classifying viruses in one of three
domains rather than in a fourth domain?

A. Some viruses can incorporate their genome into a host’s genome.
B. Viruses are not composed of cells.
C. Viruses direct anabolic pathways of host cells.
D. Viruses are obligate parasites.
E. All of the answers are correct.

B. Viruses are not composed of cells.

Which of the following best defines a strain?

A. a population of cells with similar characteristics
B. a pure culture that is not totally identical to other cultures of the same species
C. a group of cells derived from a single parent
D. same as a species
E. a group of organisms with a limited geographical distribution

B. a pure culture that is not totally identical to other cultures of the same species

Serological testing is based on the fact that

A. the human body makes antibodies against bacteria.
B. antibodies react specifically with an antigen.
C. all bacteria have the same antigens.
D. antibodies cause the formation of antigens.
E. bacteria clump together when mixed with any antibodies.

B. antibodies react specifically with an antigen.

In the scientific name Enterobacter aerogenes, Enterobacter is the

specific epithet.
order.
family.
genus.
kingdom.

genus

Which of the following criteria is most useful in determining whether two organisms are related?

A. Both are gram-positive.
B. Both ferment lactose.
C. Both are aerobic.
D. Both are motile.
E. Each answer is equally important.

A. Both are gram-positive.

A clone is

A. genetically identical cells derived from a single cell.
B. a mound of cells on an agar medium.
C. a taxon composed of species.
D. a genetically engineered cell.
E. None of the answers is correct.

A. genetically identical cells derived from a single cell.

One of the most popular taxonomic tools is DNA fingerprinting to develop profiles of organisms. These profiles provide direct information about

A. protein composition.
B. the similarities between nucleotide sequences.
C. enzymatic activities.
D. antigenic composition.
E. the presence of specific genes.

B. the similarities between nucleotide sequences.

1. 9+2 flagella
2. Nucleus
3. Plasma membrane
4. Peptidoglycan
5. Mitochondrion
6. Fimbriae

In the table, which features are found in all Eukarya?

A. 2, 3
B. 2, 3, 5
C. 1, 4, 6
D. 3, 5
E. 1, 2, 5

B. 2, 3, 5

1. 9+2 flagella
2. Nucleus
3. Plasma membrane
4. Peptidoglycan
5. Mitochondrion
6. Fimbriae

In the table, which feature(s) is (are) found only in prokaryotes?

A. 2
B. 1, 2, 3
C. 4, 6
D. 2, 4, 5
E. 1

C. 4, 6

Use the dichotomous key in the table to identify a gram-negative coccus.

A. Staphylococcus
B. Pseudomonas
C. Streptococcus
D. Neisseria
E. Micrococcus

D. Neisseria

Into which group would you place a multicellular organism that has a mouth and lives inside the human liver?

A. Plantae
B. Fungi
C. Animalia
D. Firmicutes (gram-positive bacteria)
E. Proteobacteria (gram-negative bacteria)

C. Animalia

In the cladogram shown in the figure, which two organisms are most closely related?

A. Streptomyces and Micrococcus
B. Streptomyces and Mycobacterium
C. Micrococcus and Mycobacterium
D. Mycobacterium and Lactobacillus
E. Streptomyces and Lactobacillus

C. Micrococcus and Mycobacterium

The highest level in the taxonomic hierarchy is "Kingdom."

True
False

False

Which of the following characteristics indicates that two organisms are closely related?

A. Both are cocci.
B. Both are motile.
C. Both ferment lactose.
D. Both of their DNA can hybridize.
E. Both normally live in clams.

D. Both of their DNA can hybridize.