Question 1

Which organism is the primary vector for Borrelia burgdorferi, the bacterium that causes Lyme disease?

Accepted Answer

Blacklegged tick (Ixodes scapularis)

Question 2

Which of the following best describes the cell wall structure of Gram-negative bacteria?

Accepted Answer

Thin peptidoglycan layer surrounded by an outer membrane

Question 3

A scientist isolates a bacterium from a hydrothermal vent with water at 110°C. Which term best describes this organism?

Accepted Answer

Extremophile

Question 4

Which of the following is NOT one of Koch’s postulates for confirming a causative link between a microbe and a disease?

Accepted Answer

The microbe must be able to survive outside the host for at least 24 hours.

Question 5

Which process is responsible for the initial increase of oxygen in Earth’s atmosphere?

Accepted Answer

Oxygenic photosynthesis by cyanobacteria

Question 6

A bacterial strain is found to have acquired a gene coding for a toxin, making it pathogenic. What is this ability to cause disease called?

Accepted Answer

Virulence

Question 7

Which of the following best explains why antibiotics are less effective against bacteria in biofilms?

Accepted Answer

Biofilms create a polysaccharide-rich matrix that shields bacteria from antibiotics.

Question 8

Which metabolic strategy is used by organisms that obtain energy from inorganic molecules and carbon from CO$_2$?

Accepted Answer

Chemolithoautotrophy

Question 9

What is the main ecological consequence of nitrate pollution in aquatic environments?

Accepted Answer

Development of anaerobic 'dead zones' due to decreased oxygen

Question 10

Which of the following statements about the three-domain system is correct?

Accepted Answer

Eukarya and Archaea are more closely related to each other than to Bacteria.

Question 11

A patient presents with a bullseye-shaped rash after hiking in a forested area. Which pathogen is most likely responsible?

Accepted Answer

Borrelia burgdorferi

Question 12

Which of the following is a key role of bacteria in bioremediation?

Accepted Answer

Degrading toxic organic compounds in polluted environments

Question 13

Which method allows researchers to study bacteria and archaea that cannot be grown in pure culture?

Accepted Answer

Metagenomics (environmental sequencing)

Question 14

Which equation correctly represents the process of nitrogen fixation by bacteria?

Accepted Answer

$N_2 \rightarrow 2NH_3$

Question 15

Which lineage of bacteria is responsible for fermenting milk into yogurt and cheese?

Accepted Answer

Firmicutes

Question 16

Which of the following is a major reason why extremophiles are studied by astrobiologists?

Accepted Answer

They serve as models for understanding possible extraterrestrial life.

Question 17

Which of the following is true about the abundance of bacteria and archaea on Earth?

Accepted Answer

They are the dominant life-forms in terms of total volume of living material.

Question 18

Which of the following best describes the role of cyanobacteria in aquatic ecosystems?

Accepted Answer

They produce much of the oxygen, nitrogen, and organic compounds that feed other organisms.

Question 19

Which of the following is a plausible multi-step scenario for the development of antibiotic resistance in bacteria?

Accepted Answer

Bacteria acquire resistance genes through horizontal gene transfer, then form biofilms that further protect them from antibiotics.

Prokaryotic Diversity, Pathogenicity, and Ecological Impact: Study Notes for General Biology

Study Guide - Practice Questions