Question 1

Which of the following statements best describes the main goal of modern taxonomy in microbiology?

Accepted Answer

To reflect phylogenetic hierarchy by emphasizing genetic relationships among organisms.

Question 2

Carl Woese’s classification system introduced the concept of domains based on which molecular evidence?

Accepted Answer

Comparison of rRNA nucleotide sequences

Question 3

Which of the following is NOT a characteristic of prokaryotic cells?

Accepted Answer

Presence of a membrane-bound nucleus

Question 4

Which group of eukaryotic microbes is primarily responsible for carbon fixation in aquatic ecosystems?

Accepted Answer

Algae

Question 5

A scientist isolates a microorganism that thrives at 90°C and in high salt concentrations. Which group does this organism most likely belong to?

Accepted Answer

Thermophilic and halophilic archaea

Question 6

Which of the following best explains why microbiologists study parasitic helminths?

Accepted Answer

They are small multicellular eukaryotes that cause significant human diseases.

Question 7

Which of the following statements about viruses is TRUE?

Accepted Answer

Viruses have both extracellular (virion) and intracellular states.

Question 8

Which of the following is a distinguishing feature of fungi compared to algae?

Accepted Answer

Fungi have cell walls composed of chitin.

Question 9

A lichen is best described as:

Accepted Answer

A partnership between a fungus and a photosynthetic microbe.

Question 10

Which of the following is a correct pairing of a deeply branching bacterial trait and its significance?

Accepted Answer

Thermophily; adaptation to early Earth environments

Question 11

Which of the following statements about prions is correct?

Accepted Answer

Prions are proteinaceous infectious agents that cause spongiform encephalopathies.

Question 12

Which of the following best describes the main difference between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram-negative bacteria are the largest and most diverse group, including Proteobacteria.

Question 13

Which of the following is a function of methanogenic archaea in the environment?

Accepted Answer

Conversion of carbon dioxide and hydrogen gas to methane

Question 14

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

Accepted Answer

Ability to perform photosynthesis

Question 15

A researcher discovers a unicellular organism with 80S ribosomes, a nucleus, and no cell wall. Which group does this organism most likely belong to?

Accepted Answer

Protozoa

Question 16

Which of the following best explains why viroids are pathogenic in plants?

Accepted Answer

Their RNA binds complementary plant RNA, leading to degradation and disease.

Question 17

Which of the following is a correct statement about the role of fungi in the environment?

Accepted Answer

Fungi decompose dead organisms and recycle nutrients as saprobes.

Question 18

Which of the following best describes the locomotion of amoebae?

Accepted Answer

Movement by pseudopods

Question 19

Which of the following is a unique feature of halophilic archaea?

Accepted Answer

They require high concentrations of NaCl to maintain cell wall integrity.

Question 20

Which of the following best explains why viruses are considered acellular?

Accepted Answer

They lack a cytoplasmic membrane, cytosol, and organelles.

Microbial Diversity: Classification, Structure, and Unique Groups

Study Guide - Practice Questions