Question 1

Which of the following best explains why salt is used as a preservative for foods such as meats and pickles?

Accepted Answer

Salt causes prokaryotic cells to lose water by osmosis, leading to plasmolysis and inhibiting their growth.

Question 2

A scientist isolates a prokaryote with a cell wall containing a thick layer of peptidoglycan and no outer membrane. Which type of bacteria is this most likely to be?

Accepted Answer

Gram-positive bacteria

Question 3

Which structure allows prokaryotes to survive harsh conditions such as extreme heat, drought, or radiation for centuries?

Accepted Answer

Endospore

Question 4

A patient is infected with a bacterium that is resistant to multiple antibiotics. Which genetic element is most likely responsible for this resistance?

Accepted Answer

R plasmid

Question 5

Which of the following best describes the process of horizontal gene transfer in prokaryotes?

Accepted Answer

The movement of genetic material between different species, often via transformation, transduction, or conjugation.

Question 6

Which metabolic mode is correctly matched with its energy and carbon sources?

Accepted Answer

Photoautotroph: energy from light, carbon from $CO_2$

Question 7

A bacterium is found living in a hot spring at 95°C. Which group is it most likely to belong to?

Accepted Answer

Extreme thermophiles (Archaea)

Question 8

Which of the following statements about nitrogen fixation is correct?

Accepted Answer

It is the process by which certain prokaryotes convert atmospheric $N_2$ into ammonia ($NH_3$).

Question 9

Which of the following best explains why antibiotics that target peptidoglycan are generally harmless to human cells?

Accepted Answer

Human cells lack peptidoglycan in their cell walls.

Question 10

A researcher discovers a new prokaryote that can use $O_2$ for cellular respiration but can also survive by fermentation when $O_2$ is absent. This organism is best described as a(n):

Accepted Answer

Facultative anaerobe

Question 11

Which of the following is an example of exaptation in prokaryotes?

Accepted Answer

The evolution of bacterial flagella from proteins originally used in secretion systems.

Question 12

Which of the following is a real-world consequence of biofilm formation by prokaryotes?

Accepted Answer

Biofilms can cause chronic, antibiotic-resistant infections on medical devices.

Question 13

Which of the following best describes the role of chemoheterotrophic prokaryotes in the environment?

Accepted Answer

They decompose dead organisms and recycle nutrients.

Question 14

A patient is diagnosed with a bacterial infection caused by a gram-negative bacterium. Which of the following is a likely characteristic of this bacterium?

Accepted Answer

It has an outer membrane and is more resistant to certain antibiotics.

Question 15

Which of the following is a correct statement about the genetic material of prokaryotes?

Accepted Answer

Prokaryotes typically have a single circular chromosome located in the nucleoid region.

Question 16

Which of the following is an example of mutualism involving prokaryotes and humans?

Accepted Answer

Intestinal bacteria synthesize vitamins and aid in digestion for their human host.

Question 17

Which of the following statements about the CRISPR-Cas9 system is correct?

Accepted Answer

It is a prokaryotic defense mechanism against viruses that has been adapted for gene editing in research.

Question 18

Which of the following best explains why rapid reproduction and mutation contribute to the evolution of antibiotic resistance in bacteria?

Accepted Answer

Short generation times and large populations increase the chance that mutations conferring resistance will arise and spread quickly.

Question 19

A bacterium that obtains energy from inorganic chemicals and carbon from $CO_2$ is classified as a:

Accepted Answer

Chemoautotroph

Question 20

Which of the following is a real-world application of prokaryotes in biotechnology?

Accepted Answer

Using bacteria to clean up oil spills through bioremediation.

Study Guide: Bacteria and Archaea (Campbell Biology, Chapter 27)

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