Question 1

Which of the following best describes the difference between taxonomy and systematics in microbiology?

Accepted Answer

Taxonomy is the science of classifying organisms based on similarities, while systematics (phylogeny) is the study of their evolutionary history.

Question 2

Which event led to the introduction of the term 'prokaryote' in microbiology?

Accepted Answer

The need to distinguish cells without a nucleus in 1937.

Question 3

According to Woese's three-domain system, which of the following is NOT classified as a eukaryote?

Accepted Answer

Bacteria

Question 4

Which of the following statements about the origin of eukaryotes is correct?

Accepted Answer

Eukaryotes originated from infoldings of prokaryotic plasma membranes and endosymbiotic bacteria developed into organelles.

Question 5

Which of the following is a defining feature of the domain Archaea?

Accepted Answer

Ability to survive in extreme environments such as high salinity or temperature

Question 6

Which method is most appropriate for identifying bacteria that cannot be cultured in the laboratory?

Accepted Answer

Nucleic Acid Amplification Tests (NAAT) using PCR

Question 7

A scientist is comparing the DNA base composition of two bacterial species. If both have 60% guanine + cytosine, what can be inferred?

Accepted Answer

They are closely related, but further analysis is needed for species identification.

Question 8

Which of the following best describes the principle of DNA-DNA hybridization in microbial classification?

Accepted Answer

It measures the ability of DNA strands from one organism to hybridize with those from another; a high degree of hybridization (e.g., 70%) indicates the same species.

Question 9

Which of the following is NOT a characteristic used to classify viruses?

Accepted Answer

Presence of a cell wall

Question 10

A clinical laboratory receives a sample suspected of containing a pathogenic bacterium. Which of the following steps is LEAST likely to be useful for initial identification?

Accepted Answer

Sequencing the entire genome immediately

Question 11

Which of the following statements about binomial nomenclature is correct?

Accepted Answer

It is used worldwide to consistently and accurately name organisms using genus and specific epithet.

Question 12

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

Accepted Answer

Morphological characteristics do not reflect evolutionary history as accurately as molecular methods.

Question 13

Which of the following laboratory techniques is used to differentiate between species and strains within a species based on antigen-antibody reactions?

Accepted Answer

Serological testing (e.g., slide agglutination test)

Question 14

A patient’s serum is tested for antibodies against HIV using a laboratory technique that separates proteins by size and detects specific antibodies. Which method is being used?

Accepted Answer

Western blotting

Question 15

Which of the following is a correct statement about the taxonomic hierarchy?

Accepted Answer

Order is more specific than class but broader than family.

Question 16

Which of the following best describes the use of a molecular clock in phylogenetic analysis?

Accepted Answer

It uses the accumulation of mutations in genomes to estimate evolutionary divergence.

Question 17

Which of the following is a practical application of phage typing in clinical microbiology?

Accepted Answer

Identifying bacterial strains based on susceptibility to specific bacteriophages

Question 18

Which of the following statements about the classification of eukaryotes is correct?

Accepted Answer

Protista is a catchall kingdom for a variety of organisms, grouped into clades based on rRNA.

Question 19

Which laboratory method uses differences in electrical conductivity or fluorescence to distinguish between microbial species?

Accepted Answer

Flow cytometry

Question 20

A dichotomous key is used in microbiology for which of the following purposes?

Accepted Answer

To identify organisms based on a series of successive questions

Classification of Microorganisms (Chapter 10): Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards