Question 1

Which of the following statements best describes the main difference between systematics (phylogeny) and taxonomy?

Accepted Answer

Taxonomy is the science of classifying organisms, while systematics studies their evolutionary relationships.

Question 2

According to the three-domain system developed by Woese, which of the following groups is NOT classified under the domain Eukarya?

Accepted Answer

Methanogens

Question 3

Which of the following characteristics is unique to Archaea and not found in Bacteria or Eukarya?

Accepted Answer

Membrane lipids composed of branched carbon chains attached to glycerol by ether linkage

Question 4

A scientist is using DNA-DNA hybridization to compare two bacterial species. If the degree of hybridization is 80%, what does this indicate?

Accepted Answer

The two species are likely the same species.

Question 5

Which of the following is the correct order of the taxonomic hierarchy from broadest to most specific?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 6

Which method would be most appropriate for identifying a microorganism that cannot be cultured in the laboratory?

Accepted Answer

Nucleic Acid Amplification Test (NAAT) using PCR

Question 7

A clinical laboratory receives a blood sample suspected of containing a pathogenic bacterium. Which of the following steps should be performed FIRST to ensure accurate identification?

Accepted Answer

Use transport media to collect and transport the sample to the laboratory.

Question 8

Which of the following best explains why viruses are not classified within any of the three domains?

Accepted Answer

They are not composed of cells and require a host cell for replication.

Question 9

A patient is suspected of having Lyme disease. Which laboratory technique would be most appropriate to confirm the diagnosis by detecting antibodies in the patient's serum?

Accepted Answer

Western blotting

Question 10

Which of the following statements about binomial nomenclature is correct?

Accepted Answer

The genus name is capitalized and the species name is lowercase.

Question 11

A researcher is using a dichotomous key to identify an unknown bacterium. What is the primary advantage of using this tool?

Accepted Answer

It allows identification based on a series of successive questions about characteristics.

Question 12

Which of the following laboratory techniques is most useful for distinguishing between closely related bacterial strains within the same species?

Accepted Answer

Serological testing

Question 13

A mass spectrophotometer is used in a clinical lab to identify a yeast sample. What is the principle behind this method?

Accepted Answer

It compares the mass spectral data to a database of known organisms.

Question 14

Which of the following is a correct statement about the use of rRNA sequencing in microbial classification?

Accepted Answer

It provides information about evolutionary relationships among organisms.

Question 15

A bacterial sample is subjected to a slide agglutination test. What result would indicate a positive identification?

Accepted Answer

The bacteria agglutinate (clump) when mixed with specific antibodies.

Question 16

Which of the following best describes the function of a molecular clock in phylogenetic studies?

Accepted Answer

It estimates evolutionary divergence based on the accumulation of mutations in genomes.

Question 17

A clinical microbiologist is using flow cytometry to analyze a sample. Which property is most likely being measured?

Accepted Answer

Differences in electrical conductivity or fluorescence between species.

Question 18

Which of the following equations correctly represents the relationship between the base composition of DNA?

Accepted Answer

$$GC + AT = 100\%$$

Question 19

A scientist is using a DNA chip (microarray) to detect pathogens in a sample. What is the key principle behind this technology?

Accepted Answer

Hybridization between DNA probes on the chip and DNA in the sample, detected by fluorescence.

Question 20

Which of the following best explains why morphological characteristics are less useful for determining phylogenetic relationships among prokaryotes?

Accepted Answer

Morphological characteristics are often similar due to convergent evolution and do not reflect genetic relatedness.

Classification of Microorganisms: Taxonomy, Phylogeny, and Identification Methods

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