Question 1

Which of the following statements best explains why Archaea are more closely related to Eukarya than to Bacteria?

Accepted Answer

Archaea and Eukarya share similar membrane lipid linkages and possess histones associated with DNA.

Question 2

A bacterium that obtains energy from sunlight and carbon from organic compounds is classified as a:

Accepted Answer

Photoheterotroph

Question 3

Which process is responsible for the movement of genes from one prokaryotic species to another, significantly increasing genetic diversity?

Accepted Answer

Horizontal gene transfer

Question 4

Gram-positive bacteria are more sensitive to penicillin because:

Accepted Answer

They have a thick peptidoglycan layer that is targeted by penicillin.

Question 5

Which of the following best describes the ecological role of cyanobacteria in aquatic environments?

Accepted Answer

They are the only prokaryotes that generate oxygen as a product of photosynthesis.

Question 6

A scientist discovers a microorganism living in a hot spring with temperatures above 80°C. This organism is most likely a(n):

Accepted Answer

Thermophile

Question 7

Which of the following is NOT a possible shape for a bacterial cell?

Accepted Answer

Cuboidal (cube-shaped)

Question 8

A marine worm has no mouth, gut, or anus, and depends entirely on bacteria inside its body for food and waste recycling. This is an example of:

Accepted Answer

Mutualism

Question 9

Which of the following best describes the process of conjugation in bacteria?

Accepted Answer

Direct transfer of DNA from one cell to another through a pilus

Question 10

Methanogens are important in the carbon cycle because they:

Accepted Answer

Produce methane as a metabolic byproduct in anaerobic conditions.

Question 11

Which of the following is a correct description of an obligate anaerobe?

Accepted Answer

Cannot tolerate oxygen and lives only in its absence.

Question 12

Which of the following is a real-world example of horizontal gene transfer impacting human health?

Accepted Answer

The spread of antibiotic resistance genes among pathogenic bacteria.

Question 13

Which of the following best describes the role of decomposers in the ecosystem?

Accepted Answer

They break down dead organisms, releasing minerals for reuse.

Question 14

A bacterium that can survive in both the presence and absence of oxygen is classified as a(n):

Accepted Answer

Facultative aerobe

Question 15

Which of the following is NOT a function performed by bacteria in the human microbiome?

Accepted Answer

Causing all digestive processes without human enzymes

Question 16

Which of the following is true regarding the evolution of mitochondria and plastids?

Accepted Answer

Mitochondria originated from proteobacteria, and plastids from cyanobacteria.

Question 17

Which of the following best describes a chemoautotroph?

Accepted Answer

Obtains energy from inorganic chemicals and carbon from CO$_2$

Question 18

Which of the following is a plausible consequence if nitrogen-fixing bacteria were eliminated from an ecosystem?

Accepted Answer

Plants would be unable to obtain biologically usable nitrogen, reducing productivity.

Question 19

Which of the following is NOT a type of symbiotic relationship involving bacteria?

Accepted Answer

Predation

Question 20

Which process releases carbon dioxide into the atmosphere? (Select the best answer.)

Accepted Answer

Both respiration and decomposition

Bacteria and Archaea: Diversity, Structure, and Ecological Roles

Study Guide - Practice Questions