Deck 10: Identifying and Classifying Microorganisms

Question 1

The name Lactococcus (Streptococcus) lactis

A) indicates that Streptococcus is the old genus name.
B) indicates that the subgenus is Streptococcus.
C) indicates that the family is Lactococcus.
D) indicates that Lactococcus is the old class name.
E) indicates that Lactis is the strain.

Answer 1

A

Question 2

Which technique(s) is/are used to help identify and classify bacteria?

A) Microscopic examination
B) Culture characteristics
C) Biochemical tests
D) Nucleic acid analysis
E) All of the choices are correct.

Answer 2

E

Question 3

Mycobacterium tuberculosis is one of the few species of bacteria that

A) is encapsulated.
B) is acid-fast.
C) stains Gram-negative.
D) stains Gram-positive.
E) lacks a peptidoglycan cell wall.

Answer 3

B

Question 4

In 1908 Orla-Jensen suggested that bacteria be grouped according to their

A) arrangement.
B) morphology.
C) physiology.
D) Gram stain.
E) flagella.

Question 5

In 1970 Stanier proposed that classification be based on

A) evolution.
B) Gram stain.
C) physiology.
D) DNA sequence.
E) flagella.

Question 6

A selective growth medium

A) allows only certain bacteria to grow.
B) allows all bacteria to grow.
C) allows no bacteria to grow.
D) accentuates differences between the growing bacteria.
E) is cultured anaerobically.

Question 7

Very often clinically relevant information may be obtained by examining

A) a wet mount.
B) the size and shape of the organism.
C) the sequence of proteins.
D) the transformation ability.
E) a wet mount AND the size and shape of the organism.

Question 8

Intracellular Gram-negative diplococci found in a urethral sample from a male is indicative of

A) Escherichia coli.
B) Pseudomonas aeruginosa.
C) Streptococcus pneumoniae.
D) Neisseria gonorrhoeae.
E) Staphylococcus epidermidis.

Question 9

From most general to most specific, which is the correct order?

A) Phylum, class, kingdom, order, family, genus, species
B) Kingdom, phylum, class, order, family, genus, species
C) Kingdom, phylum, family, class, order, genus, species
D) Kingdom, order, family, genus, phylum, class, species
E) Genus, species, class, order, phylum, kingdom, family

Question 10

An early attempt by Cohn at bacterial classification grouped bacteria according to their

A) biochemistry.
B) Gram stain.
C) shape.
D) arrangement.
E) size.

Question 11

Streptococcus pyogenes would be

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 12

A soluble greenish pigment is produced by

A) Serratia marcescens.
B) Pseudomonas aeruginosa.
C) Escherichia coli.
D) all streptococci.
E) Streptococcus pneumoniae.

Question 13

Media that change color as a result of the biochemical activity of growing bacteria

A) usually contain a pH indicator.
B) usually contain blood.
C) usually require the addition of various reagents before the color is evident.
D) contain a colorless reagent that breaks down.
E) are always selective media.

Question 14

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

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

Question 15

The three domain classification scheme uses

A) order, phylum, class.
B) Archaea, Bacteria, Eukarya.
C) Plants, Animals, Bacteria.
D) Protista, Prokaryotae, Fungi.
E) Bacteria, Archaea, Animalia

Question 16

Gram-positive encapsulated diplococci found in sputum are likely

A) Escherichia coli.
B) Pseudomonas aeruginosa.
C) Streptococcus pneumoniae.
D) Neisseria gonorrhea.
E) Bacillus cereus.

Question 17

In higher organisms, successful mating can occur between members of the same

A) genus.
B) species.
C) class.
D) order.
E) family.

Question 18

The reference for taxonomic descriptions of bacteria is

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 19

The basic taxonomic unit in the classification scheme of plants and animals is

A) kingdom.
B) class.
C) order.
D) genus.
E) species.

Question 20

Woese

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 21

Various strains of E. coli

A) may cause disease.
B) may be harmless.
C) are all exactly the same.
D) are all very different from one another.
E) may cause disease AND may be harmless.

Question 22

Nucleic acid techniques have great power as diagnostic tools because they may be

A) used to differentiate species.
B) quick and easy to perform.
C) used to enhance the growth of bacteria.
D) used to inhibit the growth of certain bacteria.
E) All of the answer choices are correct.

Question 23

DNA probes have been very useful in

A) coding the DNA of organisms grown in vivo.
B) identifying organisms in pure culture.
C) detecting toxins.
D) diagnosing diseases of protozoa.
E) sequencing rRNA genes.

Question 24

The relatedness of organisms determined by counting common characteristics

A) is called evolutionary taxonomy.
B) is called amino acid sequencing.
C) is called DNA sequencing.
D) is called numerical taxonomy.
E) is called taxonomical history.

Question 25

To study the phylogeny of eukaryotes,

A) 16S rRNA is used.
B) 18S rRNA is used.
C) 40S rRNA is used.
D) 80S rRNA is used.
E) 70S rRNA is used.

Question 26

Modern approaches to evolutionary taxonomy often involve

A) biochemical differences.
B) comparison of DNA or RNA.
C) protein similarities.
D) lactose fermentation abilities.
E) staining techniques.

Question 27

APIᵀᴹ, Enterotubeᵀᴹ, and Vitekᵀᴹ are all

A) methods for extracting DNA from bacteria.
B) used to measure gas production.
C) commercially available methods used to identify bacteria.
D) used to show the presence of bacteria in a sample.
E) methods for extracting protein from bacteria.

Question 28

The more closely related two organisms are,

A) the less likely they belong to one genus.
B) the more similar their nucleic acid sequence.
C) the less similar their nucleic acid sequence.
D) the more they are phenotypically similar.
E) the less they are phenotypically similar.

Question 29

A breath test assaying for radioactive carbon dioxide may be used to indicate the presence of

A) E. coli.
B) Pseudomonas species.
C) Streptococcus pyogenes.
D) Helicobacter pylori.
E) Bacillus cereus.

Question 30

Organisms that grow very slowly, cannot be cultured, are present in very small numbers, or are mixed with a number of other bacteria may still be identified using

A) Southern blotting.
B) replica plating.
C) PCR.
D) the Ames test.
E) positive selection.

Question 31

Sequencing of rRNA is useful for

A) determining evolutionary relationships AND determining protein sequences.
B) determining protein sequences AND identification of unknown bacteria.
C) determining evolutionary relationships AND determining serological relationships.
D) determining serological relationships AND determining protein sequences.
E) determining evolutionary relationships AND identification of unknown bacteria.

Question 32

Phenotypically identical bacteria

A) are genetically exactly the same.
B) may be told apart by DNA sequence analysis.
C) have similar protein profiles.
D) cannot be told apart by any means.
E) are referred to by the strain O157:H7.

Question 33

Strain differences are helpful in

A) understanding replica plating.
B) carrying out electrophoresis.
C) performing transformation in the laboratory.
D) initiating transduction in E. coli.
E) tracing the source of outbreaks of disease.

Question 34

The point at which two organisms diverged from a common ancestor

A) can be determined by comparing the nucleic acid sequences.
B) depends on transcriptional and translational control.
C) depends on metabolic activity and antibiotic resistance.
D) is determined on MacConkey's media.
E) is impossible to determine.

Question 35

Phage typing

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 36

In E. coli O157:H7, the O157:H7 refers to the

A) specific type of DNA present.
B) specific genus.
C) general family.
D) the specific LPS and flagella type present.
E) pathogenic ability.

Question 37

E. coli 0157:H7 produces clear colonies on MacConkey agar, while common strains of the organism produce pink colonies on this medium. The organism stains pink in the Gram stain. Select the True statement, given this information.

A) E. coli 0157:H7 is Gram-positive AND is a normal constituent of the intestinal tract.
B) E. coli 0157:H7 is a normal constituent of the intestinal tract AND does not ferment sorbitol.
C) E. coli 0157:H7 does not ferment sorbitol AND is Gram negative.
D) E. coli 0157:H7 does not ferment sorbitol AND is Gram-positive.
E) E. coli 0157:H7 produces a toxin AND is a normal constituent of the intestinal tract.

Question 38

Which of the rRNA molecules has proven the most useful in taxonomy/identification?

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

Question 39

Serological methods

A) are useful in identifying bacteria.
B) rely on the specificity of an antibody-antibody interaction.
C) may be simple but are always time consuming.
D) can rarely be used to identify bacteria.
E) All of the answer choices are correct.

Question 40

Two isolates with identical RFLPs are considered

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

Question 41

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

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 42

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

Question 43

A sample must contain many microorganisms in order for them to be seen any using microscopy techniques. Why is this so?

A) The area on a microscope slide is very large compared to the relative size of microbes, and you take a very small amount of your sample to place on the slide surface. Therefore, you must have a large number of microbes initially in the culture to increase the chances that you'll be able to see bacteria on the slide.
B) Bacteria are very small. It is only possible to see them if there is a large biofilm of them on the slide. If you don't have a LOT of them, how are you going to see them?
C) This statement is misleading. Microscopy allows us to magnify a specimen to the point where we would be able to visualize even just a few microbes on the surface of the slide. Even if there are only a few microbes in a sample, we could easily visualize them with a microscope.
D) Microscopes only magnify objects on the slide. If you don't have a lot of microbes on the slide surface, you can't magnify the specimen enough to see them as individual cells.
E) When bacteria are placed on a slide, they automatically swarm together into one area of the slide, allowing them to be seen. If there are too few bacteria in the sample, they are unable to swarm effectively and thus cannot be seen, even with staining.

Question 44

Why are molecular methods particularly useful for identification of microbes that are difficult to grow?

A) While all microbes can (and should) be grown for identification purposes, sometimes it's simply faster to use a molecular technique.
B) They AREN'T useful-growing a microbe is clearly the only way to properly identify it.
C) Since all microbes have DNA, and we can often detect and identify them through even very small amounts of their DNA, molecular methods allow us to identify microbes even when they can't be grown at all.
D) Molecular methods are far cheaper methods than growing microbes for identification.

Question 45

rRNA sequence comparisons are useful for determining evolutionary relationships.

Question 46

Phylogenetic relationships between prokaryotes are most accurately determined using

A) phenotypic characterizations.
B) genotypic information.
C) the fossil record.
D) carbon dating.
E) phenotypic characterizations AND genotypic information.

Question 47

The three domain systems consist of Archaea, Bacteria, and Eukarya.

Question 48

Streptococcus pyogenes can be easily distinguished microscopically from other Streptococcus species.

Question 49

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

Question 50

All known species of bacteria are described in Bergey's Manual of Systematic Bacteriology.

Question 51

Please select the False statement regarding taxonomic hierarchy.

A) A species is a group of closely related strains or an organism; it is the basic unit of taxonomy.
B) A genus is a collection of related species.
C) A phylum is a collection of similar classes; it may also be called a division.
D) A domain is a collection of similar kingdoms; there are three domains: Bacteria, Archaea, and Animalia.
E) A kingdom is a group of several phyla or divisions; a collection of similar kingdoms makes up a domain.

Question 52

Explain the difference between a biotype and a serotype.

A) A biotype is the living type of microorganism identified, while the serotype is an individual's type of blood serum.
B) A biotype is the type of biological environment a microbe will grow in, while the serotype is the type of blood serum that the microbe can grow in.
C) A biotype is the particular phenotypic traits and characteristic structures of a biological microorganism, while the serotype is the list of molecules the microbe is able to make and secrete into the serum of an infected individual.
D) A biotype is the biochemical profile of a particular microorganism, while the serotype is the difference in its surface structures/antigens that will lead to separate immune responses from an organism (characterized by presence of different antibodies in the individual's serum).
E) There is no real difference between a biotype and a serotype. These two words mean essentially the same thing and can be used interchangeably.

Question 53

Serratia marcescens are red when incubated at 37°C.

Question 54

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

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.

Question 55

If each of two bacteria have a GC content of 50%, they are both definitely closely related.

Question 56

Which statement regarding the Gram stain is False?

A) A Gram stain may give sufficient information to start appropriate antibiotic treatment-for example a Gram-positive diplococcus in sputum is likely to be Streptococcus pneumoniae.
B) A Gram stain can sometimes be used to make a diagnosis-for example a Gram-negative diplococcus in WBC from urethral discharge is Neisseria gonorrhoeae.
C) Gram staining can be used to differentiate intestinal normal microbiota from pathogens-for example differentiating E. coli from Salmonella enterica.
D) In most cases, Gram staining is not sufficient to identify an organism-for example, Gram-positive staphylococci on skin may be either S. aureus or S. epidermidis.
E) Medically important bacteria can seldom be identified by Gram staining alone-for example the throat may harbor Streptococcus pyogenes (pathogen) as well as Streptococcus species that are normal microbiota.

Question 57

When DNA probes are used to identify bacterial DNA similarities by hybridization, the probe DNA is heated and the template DNA is treated to separate the two strands. Why would the probe DNA be heated?

A) This is the only way to properly label the probe DNA.
B) The probe may contain parts that are double-stranded. Heating it up breaks the hydrogen bonds holding the strands together, creating single-stranded sequences that hybridize with their complementary targets.
C) Heating it up activates the tag on the probe DNA before it hybridizes to the bacterial template DNA.
D) DNA hybridization can only take place at high temperatures, so all the DNA must be heated up prior to hybridization.
E) The probe may contain many parts that are single-stranded. Heating it up creates hydrogen bonds that hold the probe tightly to its complementary target sequences.

Question 58

A DNA similarity of 75% between two organisms

A) suggests the organisms are closely related at the species level.
B) suggests the organisms are not closely related at all.
C) suggests the organisms may or may not be related.
D) means the GC content in both organisms is 45%.
E) means the GC content in one organism is 75% and 25% in the other.

Question 59

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

Question 60

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

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 61

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?

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

Question 62

Please select the False definition regarding microbial identification.

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 63

Which of the following is NOT a method used to differentiate E. coli O157:H7 from other strains based directly on genotype?

A) Fluorescence in situ hybridization (FISH)
B) Nucleic acid amplification tests (NAATs)
C) Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS)
D) 16S rRNA gene sequencing
E) Radioisotope-labeled probes or fluorescent dye-labeled probes

Question 64

You tell the patient that his sample contains white blood cells in which Gram-negative diplococci can be detected. Your patient asks how you obtained this result and you tell him you

A) performed a Gram stain.
B) performed an acid-fast stain.
C) cultured his discharge on Gram-positive medium.
D) cultured his discharge on Gram-negative medium.
E) performed an antibiogram.

Question 65

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

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

Question 66

You have identified the causative organism of the outbreak as E. coli. In an effort to characterize the strain of the organism involved, you do different tests. The results are as follows:
Gram stain-Gram-negative rods
Oxidase test-negative
Lactose fermentation-positive
Serological testing-O157:H7
Colony morphology-smooth
Creamy colonies
RFLPs-E. coli O157:H7
Antibiogram-resistant to ampicillin.
Which test(s) confirm the identity of the organism at the strain level?

A) Gram stain AND antibiogram
B) Serological testing AND colony morphology
C) RFLPs AND serological testing
D) Oxidase test AND RFLPs
E) Lactose fermentation AND oxidase test

Question 67

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.

Question 68

Strains of an organism can always reliably be identified using RFLPs (restriction fragment length polymorphisms).

Question 69

You are working in a clinical lab. Two E. coli samples are sent to you for analysis and you are asked to determined whether they are the same strain. You perform an antibiogram and find that the two samples exhibit the same sensitivity to the antibiotics you use in the procedure. This indicates

A) the organisms are likely the same strain but you need to confirm this with other methods.
B) the organisms are likely different strains but you need to confirm this with other methods.
C) the two organisms are not likely to be susceptible to the same bacteriophages.
D) the two organisms will show different results if they are Gram stained.
E) the organisms are the same strains but they will react differently in serology tests.

Question 70

You patient tells you he has heard that N. gonorrhoeae is increasingly difficult to treat because of resistance to antibiotics. He asks whether it is possible to determine which antibiotics will be affective in treating his infection. You tell him that ________ indicate antibiotic susceptibility.

A) colony morphology
B) antibiograms
C) metabolic assays
D) 16S rRNA sequencing
E) MALDI-TOF MS assays

Question 71

You isolate a prokaryote. After performing analysis on the organism, you cannot find a description matching that of your organism in the reference text Bergey's Manual of Systematic Bacteriology. This suggests that you have likely isolated a new organism.

Question 72

If you were the lab technician trying to identify the causative organism of this foodborne outbreak, would you inoculate several biochemical tests at the same time, or would you inoculate each test after getting the results from the previous test?

A) I would inoculate each test after obtaining results from the last one because the tests are very quick and give instant results, and doing one test at a time will avoid confusion in the results.
B) I would inoculate several tests simultaneously, because most biochemical tests require at least 18 hours of incubation, so inoculating several tests simultaneously saves time and also aids in conclusive identification.
C) I would inoculate each test after obtaining results from the last one because the tests are extremely expensive so the fewer tests I can do, the less money I have to invest in the identification process.
D) I would inoculate several tests simultaneously, because these tests can only be analyzed using specialized equipment, so I need to have the tests ready at the same time. 
E) I would inoculate each test after obtaining results from the last one because these tests are very time consuming and difficult to set up, so it would be more practical to take this approach.

Question 73

In a MALDI-TOF assay, 

A) antibodies are used to detect specific proteins and polysaccharides, particularly those that make up surface structures.
B) a microorganism's proteins are separated and sorted by mass to generate a profile that provides a fast way to identify a colony.
C) part of a colony is transferred to a microscope slide, and a drop of hydrogen peroxide (H₂O₂) is added to it to test for catalase.
D) specimens are inoculated onto differential media and a set of biochemical tests are used to identify a microorganism.
E) the nucleotide sequence of ribosomal RNA molecules (rRNAs), or the DNA that encodes them (rDNAs), is used to identify microbes. 

Question 74

 Based on the Gram stain results, you tell your patient that you think he has gonorrhea, a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. You are able to make this diagnosis based on

A) the fact that N. gonorrhoeae is the only Gram-negative diplococcus found within white blood cells in the male urethra.
B) signs and symptoms AND the fact that there are bacteria in the urethral discharge.
C) signs and symptoms AND because N. gonorrhoeae is the only Gram-negative diplococcus found within white blood cells in the male urethra.
D) signs and symptoms AND the fact that bacteria in the discharge are Gram-positive.
E) the fact that bacteria are present in red blood cells AND because N. gonorrhoeae is the only Gram-negative diplococcus found within the male urethra.

Question 75

E. coli is a Gram-negative bacillus that is found as intestinal normal microbiota. Which of the following would not be useful for an initial step in identifying E. coli O157:H7 strains in a stool sample?

A) Gram staining, because E. coli strains will appear identical using this approach.
B) Serology, because E. coli strains all express the same antigens.
C) Growth on selective media, because all strains of E. coli will have the same metabolic capabilities.
D) RFLPs, because E. coli strains will be identical at the genome level. 
E) These methods can all be used to differentiate between E. coli strains.

Question 76

Please select the False statement regarding phenotypic approaches to identifying microorganisms.

A) Most of these methods do not require sophisticated equipment and can easily be done anywhere in the world.
B) Size, shape, and staining characteristics can give suggestive information about the identity of an organism but additional testing is usually required.
C) MALDI-TOF MS separates and sorts an organism's carbohydrates by mass, generating a profile that provides a fast way to identify an organism grown in culture.
D) A set of biochemical tests that examine the metabolic capabilities of a microorganism can be used to identify it.
E) Colony morphology can give initial clues to the identity of an organism but additional testing is required for absolute identification.

Question 77

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?

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

Question 78

You are sent three clinical samples and are asked to determine whether they are the same strain. You perform standard identification techniques but cannot come to a conclusion. You decide to do an RFLP test. You digest the genomes of the organisms with the same restriction enzyme and run a gel. Each organism yields 5 bands on the gel, of the following sizes: 
Organism A: 3 kb, 7 kb, 11 kb; 14 kb, 21 kb
Organism B: 3 kb, 7 kb, 2 kb, 8 kb, 11 kb
Organism C: 11 kb, 3 kb, 14 kb, 7 kb; 21 kb
What conclusion(s) can you make from this result?

A) Organisms A and B are likely the same strain but are different from organism C.
B) Organisms B and C are likely the same strain but are different from organism A.
C) Organisms A and C are likely the same strain but are different from organism B.
D) The organisms are all likely the same strain.
E) The organisms are all likely different strains.

Question 79

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.

Question 80

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

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%.