Deck 10: Classification of Microorganisms

Question 1

Figure 10.1

In Figure 10.1, the closest ancestor for both species ʺa.ʺ and species ʺb.ʺ would be which of the following?

A) 1
B) 2
C) 3
D) 4
E) 5

Answer 1

E

Question 2

Protists are a diverse group of organisms that are similar in

A) motility.
B) ecology.
C) rRNA sequences.
D) metabolic type.
E) None of the answers is correct.

Answer 2

C

Question 3

The arrangement of organisms into taxa

A) shows relationships to common ancestors.
B) shows degrees of relatedness between organisms.
C) is arbitrary.
D) is based on evolution.
E) was designed by Charles Darwin.

Answer 3

B

Question 4

A biochemical test, in the microbiology world, is used to determine

A) staining characteristics.
B) amino acid sequences of enzymes.
C) capability of a microbe to perform a specific enzymatic activity.
D) nucleic acid-base composition of DNA sequences.
E) All of the answers are correct.

Question 5

If two organisms have similar rRNA sequences, you can conclude that they

A) live in the same place.
B) will have different G-C ratios.
C) mated with each other.
D) will both ferment lactose.
E) evolved from a common ancestor.

Question 6

Figure 10.1

In Figure 10.1, species ʺc.ʺ is most closely related to which of the following?

A) a
B) b
C) c
D) d
E) e

Question 7

In the scientific name Enterobacter aerogenes, Enterobacter is the

A) genus.
B) order.
C) kingdom.
D) family.
E) specific epithet.

Question 8

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

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

Question 9

What is the outstanding characteristic of the Kingdom Fungi?

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

Question 10

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

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

Question 11

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

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

Question 12

Which of the following statements about archaea is FALSE?

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

Question 13

Fossil evidence indicates that prokaryotic cells first existed on the Earth

A) 350 years ago.
B) 3.5 billion years ago.
C) 3.5 × 1012 years ago.
D) 35000 years ago.
E) 3500 years ago.

Question 14

Which of the following provides taxonomic information that includes the information obtained in the others listed?

A) nucleic acid hybridization
B) nucleic acid-base composition
C) cladogram
D) biochemical tests
E) amino acid sequencing

Question 15

A genus can best be defined as

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

Question 16

Which of the following is NOT based on nucleic-acid hybridization?

A) Southern blotting
B) FISH
C) Western blotting
D) DNA chip
E) PCR

Question 17

Which of the following statements is a reason for NOT classifying viruses in one of the three domains of life (Bacteria, Archaea, Eukarya) rather than in a fourth separate domain?

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

Question 18

Which of the following characterizes the Domain Bacteria?

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

Question 19

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

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

Question 20

The phylogenetic classification of bacteria is based on

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

Question 21

Which of the following best defines a strain in microbiological terms?

A) a pure culture that is not totally identical to other cultures of the same species
B) groups of cells all derived from and identical to a single parent species
C) same as a species
D) a mixed population of cells,genetically distinct, but with highly similar phenotypic characteristics
E) a group of organisms with a limited geographical distribution

Question 22

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

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

Question 23

All of the following statements are reasons why fluorescent in situ hybridization (FISH) has become a valuable tool for environmental microbiologists EXCEPT

A) it allows observation of microbes in their natural environment in association with other microbes.
B) it allows one to obtain pure cultures of microbes.
C) it demonstrates the diversity of microbes in an environment.
D) it allows for detection of uncultured microbes.
E) All of the answers are correct.

Question 24

Figure 10.2 A nucleic acid hybridization experiment produced the following results.
In Figure 10.2, which figure shows the most closely related organisms?

A) a
B) b
C) c
D) d
E) e

Question 25

Organism A has 70 moles % G+C, and organism B has 40 moles % G+C. Which of the following can be concluded from these data?

A) The two organisms are related.
B) Their nucleic acids will completely hybridize.
C) The two organisms are unrelated.
D) The organisms make entirely different enzymes.
E) None of the answers is correct.

Question 26

Table 10.2
I. Gram-positive
A. Catalase $+$
$\quad$ 1. Acid from glucose. $\quad$ Staphylococcus
$\quad$ 2. Glucose $\quad$$\quad$$\quad$$\quad$$\quad$ Micrococcus
B. Catalase-
$\quad$ 1. Coccus. $\quad$$\quad$$\quad$$\quad$ Streptococcus
$\quad$ 2. Rod $\quad$$\quad$$\quad$$\quad$$\quad$ Lactobacillus
II. Gram-negative
A. Oxidase-
1. Acid from lactose
$\quad$ a. Uses citric acid. $\quad$$\quad$$\quad$$\quad$ Citrobacter
$\quad$ b. Citric acid $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ Escherichia
2. Lactose-
a. $\mathrm { H } _ { 2 } \mathrm {~S}$ produced
$\quad$ (1) Urease positive. $\quad$$\quad$$\quad$$\quad$ Proteus
$\quad$ (2) Urease negative $\quad$$\quad$$\quad$$\quad$ Salmonella
B. Oxidase $+$
$\quad$ 1. Rod. $\quad$$\quad$$\quad$$\quad$$\quad$ Pseudomonas
$\quad$ 2. Coccus. $\quad$$\quad$$\quad$$\quad$ Neisseria

-Use the dichotomous key in Table 10.2 to identify a gram -negative cell that ferments lactose and uses citric acid as its sole carbon source.

A) Escherichia
B) Citrobacter
C) Lactobacillus
D) Staphylococcus
E) Pseudomonas

Question 27

You discovered a unicellular organism that lacks a nucleus and peptidoglycan. You suspect the organism is in the group

A) Animalia.
B) Fungi.
C) Plantae.
D) Archaea.
E) Bacteria.

Question 28

Into which group would you place a multicellular heterotroph with chitin cell walls?

A) Bacteria
B) Fungi
C) Plantae
D) Archaea
E) Animalia

Question 29

Table 10.1 $\begin{array}{|l|l|}\hline \text { 1. } & 9+2 \text { flagella } \\\hline 2 . & \text { Nucleus } \\\hline \text { 3. } & \text { Plasma membrane } \\\hline 4 . & \text { Peptidoglycan } \\\hline 5 . & \text { Mitochondrion } \\\hline 6 . & \text { Fimbriae } \\\hline\end{array}$

-In Table 10.1, which feature(s) is (are) found only in prokaryotes?

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

Question 30

Table 10.1 $\begin{array}{|l|l|}\hline \text { 1. } & 9+2 \text { flagella } \\\hline 2 . & \text { Nucleus } \\\hline \text { 3. } & \text { Plasma membrane } \\\hline 4 . & \text { Peptidoglycan } \\\hline 5 . & \text { Mitochondrion } \\\hline 6 . & \text { Fimbriae } \\\hline\end{array}$

-In Table 10.1, which features are found in nearly all eukarya?

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

Question 31

Serological testing is based on the fact that

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

Question 32

Into which group would you place a unicellular organism that has 70S ribosomes and a peptidoglycan cell wall?

A) Animalia
B) Plantae
C) Bacteria
D) Fungi
E) Protist

Question 33

Into which group would you place a photosynthetic cell that lacks a nucleus?

A) Animalia
B) Bacteria
C) Protista
D) Fungi
E) Plantae

Question 34

A clone is

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

Question 35

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

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

Question 36

Table 10.2
I. Gram-positive
A. Catalase $+$
$\quad$ 1. Acid from glucose. $\quad$ Staphylococcus
$\quad$ 2. Glucose $\quad$$\quad$$\quad$$\quad$$\quad$ Micrococcus
B. Catalase-
$\quad$ 1. Coccus. $\quad$$\quad$$\quad$$\quad$ Streptococcus
$\quad$ 2. Rod $\quad$$\quad$$\quad$$\quad$$\quad$ Lactobacillus
II. Gram-negative
A. Oxidase-
1. Acid from lactose
$\quad$ a. Uses citric acid. $\quad$$\quad$$\quad$$\quad$ Citrobacter
$\quad$ b. Citric acid $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ Escherichia
2. Lactose-
a. $\mathrm { H } _ { 2 } \mathrm {~S}$ produced
$\quad$ (1) Urease positive. $\quad$$\quad$$\quad$$\quad$ Proteus
$\quad$ (2) Urease negative $\quad$$\quad$$\quad$$\quad$ Salmonella
B. Oxidase $+$
$\quad$ 1. Rod. $\quad$$\quad$$\quad$$\quad$$\quad$ Pseudomonas
$\quad$ 2. Coccus. $\quad$$\quad$$\quad$$\quad$ Neisseria

-Use the dichotomous key in Table 10.2 to identify a gram -negative coccus.

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

Question 37

Figure 10.3 This figure shows the results of a gel electrophoresis separation of restriction fragments of the DNA of different organisms.
In Figure 10.3, which two are most closely related?

A) 2 and 5
B) 4 and 5
C) 2 and 4
D) 1 and 3
E) 3 and 5

Question 38

Phage typing is based on the fact that

A) bacterial viruses attack only members of a specific species.
B) viruses cause disease.
C) bacteria are destroyed by viruses.
D) phages and bacteria are related.
E) Staphylococcus causes infections.

Question 39

Bacteria and Archaea are similar in which of the following?

A) sensitivity to antibiotics
B) peptidoglycan cell walls
C) plasma membrane ester linkage
D) considered prokaryotic cells
E) methionine as the start signal for protein synthesis

Question 40

Nucleic acid hybridization is based on the fact that

A) all cells have DNA.
B) a chromosome is composed of complementary strands.
C) pairing between complementary bases occurs.
D) DNA is composed of genes.
E) the strands of DNA can be separated.

Question 41

One of the advantages of some newly developed rapid identification tools is that pure cultures are not needed. Why is a pure culture necessary for biochemical tests such as the Enterotube, but not for DNA probes?

Question 42

The highest level in the current taxonomic hierarchy is ʺKingdom.ʺ

Question 43

The cell membranes of all three domains are composed of straight carbon chains attached to glycerol by ester linkage.

Question 44

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

A) Their DNA can hybridize together.
B) Both are cocci.
C) Both are motile.
D) Both ferment lactose.
E) Both normally live in clams.

Question 45

Table 10.3
Use the information given in Table 10.3 to answer the following questions. Which organisms are most closely related? On what did you base your answer? DNA from which organisms will probably hybridize?

Question 46

Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?

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

Question 47

Once a culture is purified, the next logical step in the process of identifying bacteria is biochemical testing.

Question 48

When building a cladogram, the length of the horizontal branch is based on the calculated percent similarity between organisms.

Question 49

Serological testing is used for screening bacterial isolates for similarities.

Question 50

At this point in time, scientists believe the vast majority of the domain Bacteria have been discovered.

Question 51

Pure cultures of the same species are not always identical in all ways.

Question 52

Chloroplasts possess circular DNA and reproduce by binary fission.

Question 53

As molecular techniques improve, scientists are finding it necessary to reclassify some genera.

Question 54

Data collected to date indicate that

A) marine mammals donʹt have an immune system.
B) marine mammals do not get infectious diseases.
C) new species of bacteria will not be discovered in wild animals.
D) humans and marine mammals cannot be infected by the same pathogens.
E) None of the answers is correct.

Question 55

Western blotting is an immunological test used to identify the antibodies in the serum of an individual suspected of having Lyme disease.

Question 56

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

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

Question 57

Figure 10.4 In the cladogram shown in Figure 10.4, which two organisms are most closely related?

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

Question 58

Figure 10.5
Choose one of the phylogenetic schemes in Figure 10.5 and explain why you feel it is preferable to the others.