Question 1

Which of the following best defines 'phylogeny' in the context of microbiology?

Accepted Answer

The evolutionary history and relationships among organisms.

Question 2

What is a major limitation of the two-kingdom classification system (Plantae and Animalia) when applied to microorganisms?

Accepted Answer

It fails to distinguish between prokaryotic and eukaryotic organisms.

Question 3

Which scientist is credited with introducing the three-domain system based on differences in ribosomal RNA sequences?

Accepted Answer

Carl Woese

Question 4

Which of the following is an advantage of the three-domain system over previous classification systems?

Accepted Answer

It recognizes fundamental genetic differences between Bacteria, Archaea, and Eukarya.

Question 5

Which characteristic is unique to the domain Archaea when compared to Bacteria and Eukarya?

Accepted Answer

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

Question 6

Why are scientific names (binomial nomenclature) used in microbiology?

Accepted Answer

To provide a universal and standardized way to identify organisms.

Question 7

Which of the following lists the major taxa in correct hierarchical order from broadest to most specific?

Accepted Answer

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

Question 8

A microbiologist isolates a pure culture of bacteria from a patient. Which term best describes this population if all cells are genetically identical?

Accepted Answer

Clone

Question 9

Which of the following is NOT a major characteristic used to differentiate the three kingdoms of multicellular Eukarya (Plantae, Animalia, Fungi)?

Accepted Answer

Presence of peptidoglycan

Question 10

Which statement best defines a protist?

Accepted Answer

A eukaryotic organism that is not a plant, animal, or fungus.

Question 11

Which of the following correctly differentiates a prokaryotic species from a eukaryotic species?

Accepted Answer

Eukaryotic species are defined by the ability to interbreed, while prokaryotic species are defined by genetic similarity.

Question 12

A hospital lab receives a bacterial sample and must determine its identity. Which of the following best describes the difference between classification and identification?

Accepted Answer

Classification is grouping organisms based on similarities, while identification is determining the identity of an unknown organism.

Question 13

What is the primary purpose of Bergey’s Manual in microbiology?

Accepted Answer

To serve as a reference for the classification and identification of bacteria.

Question 14

A Gram stain is performed on a bacterial sample. Which of the following best explains how staining and biochemical tests are used to identify bacteria?

Accepted Answer

They provide information about cell wall structure and metabolic capabilities.

Question 15

A patient is infected with an unknown bacterium. The lab uses a panel of antibodies to test for specific surface antigens. Which identification method is being used?

Accepted Answer

Serological testing

Question 16

A newly discovered microbe is classified by comparing its DNA sequence to known organisms. Which molecular technique is most directly used in this process?

Accepted Answer

DNA sequencing

Question 17

Which method uses labeled DNA probes to detect specific sequences in microorganisms, and can be visualized under a fluorescence microscope?

Accepted Answer

FISH (Fluorescent In Situ Hybridization)

Question 18

A microbiologist uses a dichotomous key and a cladogram to analyze bacterial samples. Which statement best differentiates these two tools?

Accepted Answer

A dichotomous key is used for stepwise identification, while a cladogram illustrates evolutionary relationships.

Question 19

A clinical lab uses PCR to amplify a specific gene from a bacterial sample. If the PCR reaction uses the equation $$N = N_0$ 	imes 2^n$$, where $$N_0 is $$the initial number of DNA molecules and $$n is $$the number of cycles, how many DNA molecules will be present after 5 cycles if the reaction starts with 10 molecules?

Accepted Answer

$$N = 10 	imes 2^5$ = 320$$ molecules

Question 20

A researcher is using DNA chips (microarrays) to identify unknown bacteria in a water sample. Which principle allows this method to work?

Accepted Answer

Hybridization of sample DNA to complementary probes on the chip

Microbiology Taxonomy and Classification Study Guide

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