Question 1

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

Accepted Answer

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

Question 2

According to the three-domain system developed by Woese, which of the following groups is NOT classified as a prokaryote?

Accepted Answer

Eukarya

Question 3

Which of the following is a key feature that distinguishes Archaea from Bacteria?

Accepted Answer

Archaea have membrane lipids with ether linkages, while Bacteria have ester linkages.

Question 4

The endosymbiont theory explains the origin of which eukaryotic organelles?

Accepted Answer

Mitochondria and chloroplasts

Question 5

Which of the following best describes the binomial nomenclature system used in scientific naming?

Accepted Answer

It uses two names: the genus and the specific epithet (species).

Question 6

A clinical laboratory receives a specimen suspected to contain a pathogenic bacterium. Which of the following identification methods would be LEAST useful if the bacterium lacks a cell wall?

Accepted Answer

Gram staining

Question 7

Which of the following statements about DNA-DNA hybridization is correct?

Accepted Answer

A hybridization value greater than 70% suggests the organisms belong to the same species.

Question 8

A patient is tested for COVID-19 using a direct ELISA. Which of the following best describes the principle of this test?

Accepted Answer

Known antibodies are used to detect the presence of viral antigens in the patient sample.

Question 9

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

Accepted Answer

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

Question 10

A rapid identification system for bacteria uses multiple biochemical tests simultaneously and assigns a code number based on the results. If a test panel has 5 groups of 3 tests each, and each positive result in a group is assigned a value of $$2^n ($$where $$n is $$the position in the group, starting from 0), what is the code for a bacterium that tests positive in the first and third tests of group 1, and only the second test of group 2?

Accepted Answer

Group 1: $$2^0$$ + $$2^2 = 1 + 4 = 5$; Group 2: 2^1$ = 2$$; Code: 5,2

Question 11

Which of the following laboratory techniques allows for the identification of bacteria without the need for culturing and can distinguish cells based on differences in fluorescence?

Accepted Answer

Flow cytometry

Question 12

A researcher is using nucleic acid amplification tests (NAATs) to detect a virus in sewage samples. Which of the following best describes the principle of this method?

Accepted Answer

NAATs use PCR to amplify specific DNA or RNA sequences, allowing detection even when the microorganism cannot be cultured.

Question 13

Which of the following is a real-world application of phage typing in clinical microbiology?

Accepted Answer

Tracing the source of a Salmonella outbreak by comparing plaque patterns

Question 14

Which of the following statements about the molecular clock concept is correct?

Accepted Answer

Mutations accumulate in a genome at a constant rate, allowing estimation of evolutionary divergence times.

Question 15

A DNA chip (microarray) is used to detect antibiotic resistance genes in a bacterial sample. Which of the following best explains how this technology works?

Accepted Answer

The chip contains thousands of DNA probes; fluorescently labeled sample DNA hybridizes to complementary probes, and fluorescence indicates the presence of specific genes.

Question 16

Which of the following is NOT a characteristic used in Bergey's Manual of Determinative Bacteriology for identifying bacteria?

Accepted Answer

Antibiotic resistance gene sequencing

Question 17

Which of the following best describes the role of rRNA sequencing in microbial classification?

Accepted Answer

It provides information about evolutionary relationships by comparing conserved genetic sequences.

Question 18

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

Accepted Answer

To identify an unknown organism by answering a series of paired questions

Question 19

Which of the following is true regarding the classification of viruses?

Accepted Answer

Viral species are defined as populations of viruses with similar characteristics that can be distinguished from other species by multiple methods.

Classification of Microorganisms: Taxonomy, Phylogeny, and Historical Systems

Study Guide - Practice Questions

Study Guide - Flashcards