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 lipids and some genetic machinery, such as histones and ribosomal proteins.

Question 2

A scientist discovers a microorganism living in a hot spring with temperatures above 80°C. Which term best describes this organism?

Accepted Answer

Thermophile

Question 3

Which process is responsible for the direct uptake of free DNA fragments from the environment by a bacterial cell?

Accepted Answer

Transformation

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

Facultative aerobe

Question 6

Which of the following is a correct match between a bacterial cell wall type and its response to penicillin?

Accepted Answer

Gram-positive bacteria are sensitive to penicillin due to their thick peptidoglycan wall.

Question 7

Which of the following equations correctly represents the process of nitrogen fixation performed by certain bacteria?

Accepted Answer

$$\mathrm{N_2$ \rightarrow NH_4$^+}$$

Question 8

Which of the following best describes mutualism?

Accepted Answer

Both organisms benefit from the association.

Question 9

A bacterium that obtains energy by oxidizing inorganic chemicals and uses CO$$_2 as $$its carbon source is classified as a:

Accepted Answer

Chemoautotroph

Question 10

Which of the following statements about horizontal gene transfer in prokaryotes is correct?

Accepted Answer

It is a major driver of genetic diversity and evolution in prokaryotes.

Question 11

Which of the following best explains why prokaryotes are important in the global carbon cycle?

Accepted Answer

They act as both producers (e.g., cyanobacteria) and decomposers, recycling organic matter.

Question 12

Which of the following is NOT a correct pairing of prokaryotic cell shape and its description?

Accepted Answer

Vibrio – filamentous chain

Question 13

Which of the following is a real-world example of a mutualistic relationship involving bacteria?

Accepted Answer

Rhizobium bacteria fixing nitrogen in the root nodules of legumes

Question 14

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

Accepted Answer

Two living bacterial cells directly transfer DNA through a pilus.

Question 15

Which of the following best describes the role of decomposer bacteria in ecosystems?

Accepted Answer

They break down dead organisms, releasing nutrients back into the environment.

Question 16

Which of the following is a correct description of a halophile?

Accepted Answer

An organism that thrives in high-salt environments.

Question 17

Which of the following is a plausible consequence of horizontal gene transfer between bacteria in a hospital setting?

Accepted Answer

Spread of antibiotic resistance genes among different bacterial species.

Question 18

Which of the following best describes the difference between aerobic and anaerobic prokaryotes?

Accepted Answer

Aerobic prokaryotes require oxygen for growth, while anaerobic prokaryotes do not tolerate oxygen.

Question 19

Which of the following is a correct sequence of events in the nitrogen cycle involving bacteria?

Accepted Answer

Nitrogen fixation $$\rightarrow$$ Nitrification $$\rightarrow$$ Denitrification

Question 20

Which of the following best explains why Gram-negative bacteria are generally more resistant to penicillin than Gram-positive bacteria?

Accepted Answer

Gram-negative bacteria have an outer membrane that restricts entry of penicillin.

Bacteria and Archaea: Diversity, Structure, and Ecological Roles

Study Guide - Practice Questions