Question 1

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

Accepted Answer

Taxonomy involves naming and classifying organisms, while systematics includes taxonomy and also studies evolutionary relationships among organisms.

Question 2

Who developed the three-domain system of classification, and what molecular data did he use?

Accepted Answer

Carl Woese; he used ribosomal RNA (rRNA) sequences.

Question 3

Which of the following is NOT a characteristic of the Domain Archaea?

Accepted Answer

They have membrane-bound organelles.

Question 4

Which example organism is correctly matched with its domain?

Accepted Answer

Methanogens – Domain Archaea

Question 5

According to the endosymbiotic theory, which organelles are believed to have originated from free-living prokaryotes?

Accepted Answer

Mitochondria and chloroplasts

Question 6

A microbiologist isolates a pure culture from a soil sample. What does the term 'culture' refer to in this context?

Accepted Answer

A population of microorganisms grown in a controlled environment.

Question 7

What is the main difference between a clone and a strain in microbiology?

Accepted Answer

A clone is a population of cells derived from a single parent cell, while a strain is a genetically distinct subgroup within a species.

Question 8

Which of the following kingdoms is NOT part of Domain Eukarya?

Accepted Answer

Bacteria

Question 9

What is the uniting feature of all organisms in Domain Eukarya?

Accepted Answer

Presence of a true nucleus and membrane-bound organelles

Question 10

Why are viruses not classified within any of the three domains of life?

Accepted Answer

They lack cellular structure and do not possess ribosomal RNA.

Question 11

A dichotomous key is used in microbiology for which purpose?

Accepted Answer

To identify organisms based on a series of paired choices about their characteristics.

Question 12

Which of the following best illustrates the application of the three-domain system in a clinical setting?

Accepted Answer

Identifying the causative agent of a hospital-acquired infection as a member of Domain Bacteria.

Question 13

Which of the following statements about the evolutionary relationships among the three domains is correct?

Accepted Answer

Archaea are more closely related to Eukarya than to Bacteria.

Question 14

Which of the following is a practical use of a dichotomous key in a microbiology laboratory?

Accepted Answer

Identifying an unknown bacterial isolate from a patient sample.

Question 15

Which of the following best explains why the endosymbiotic theory is supported by the presence of circular DNA in mitochondria?

Accepted Answer

Circular DNA is characteristic of prokaryotes, suggesting mitochondria originated from a prokaryotic ancestor.

Organism Classification: Taxonomy, Domains of Life, and Identification Methods

Study Guide - Practice Questions