Question 1

Which of the following statements best explains why bacteria and archaea are classified into separate domains?

Accepted Answer

They have striking structural and biochemical differences, such as cell wall composition and membrane lipids.

Question 2

A scientist discovers a new microorganism with a cell wall made of peptidoglycan and unbranched membrane hydrocarbons. To which domain does this organism most likely belong?

Accepted Answer

Domain Bacteria

Question 3

Which of the following best describes the process of quorum sensing in bacteria?

Accepted Answer

It is the ability of bacteria to estimate their population density using signaling molecules, triggering group behaviors like toxin production.

Question 4

Which of the following is a key difference between bacterial and archaeal flagella?

Accepted Answer

Bacterial flagella are solid and made of flagellin, while archaeal flagella are thinner and made of different proteins.

Question 5

Which of the following best explains why endospores are a challenge in food storage?

Accepted Answer

Endospores can survive boiling and other harsh conditions, allowing bacteria to germinate and produce toxins in stored food.

Question 6

Which metabolic strategy allows some prokaryotes to extract energy from inorganic molecules such as hydrogen or sulfur?

Accepted Answer

Chemolithotrophy

Question 7

A patient develops a severe infection after a puncture wound. The bacteria isolated are anaerobic, form endospores, and produce a neurotoxin. Which genus is most likely responsible?

Accepted Answer

Clostridium

Question 8

Which of the following is a mutualistic relationship involving prokaryotes?

Accepted Answer

Rhizobium bacteria fixing nitrogen in legume root nodules in exchange for sugars

Question 9

Which process allows prokaryotes to exchange genetic material without reproduction, increasing genetic diversity?

Accepted Answer

Conjugation

Question 10

Which of the following best describes why antibiotics are ineffective against viral infections?

Accepted Answer

Viruses lack the cellular structures targeted by antibiotics, such as cell walls and ribosomes.

Question 11

Which of the following is true about prions?

Accepted Answer

They are infectious proteins that can cause neurodegenerative diseases by inducing misfolding of normal proteins.

Question 12

Which of the following is a real-world example of bioremediation involving prokaryotes?

Accepted Answer

Using oil-eating bacteria to clean up an oil spill

Question 13

Which of the following best describes the structure of a typical virus?

Accepted Answer

A molecule of DNA or RNA surrounded by a protein coat, sometimes with a lipid envelope

Question 14

Which of the following is NOT a characteristic of living organisms, but is true for viruses?

Accepted Answer

They lack metabolism and cannot respond to stimuli.

Question 15

Which of the following best explains why viral infections are difficult to treat?

Accepted Answer

Viruses use the host's cellular machinery, making it hard to target the virus without harming host cells.

Question 16

Which of the following is a function of nitrogen-fixing bacteria in the environment?

Accepted Answer

Converting atmospheric nitrogen ($$N_2) $$into ammonia ($$NH_3) $$usable by plants

Question 17

Which of the following is a correct statement about viroids?

Accepted Answer

They are infectious RNA molecules that cause diseases in plants.

Question 18

A bacterial population doubles every 20 minutes under ideal conditions. If you start with 1 cell, how many cells will there be after 2 hours? Use the formula $$N = N_0$ 	imes 2$$^{(t/T)}$$, where N_0$ is the initial number, t$ is time elapsed, and T$ is the doubling time.

Accepted Answer

$$N = 1 	imes 2$$^{(120/20)}$$ = 1 	imes 2^6$ = 64$$

Question 19

Which of the following is a reason why prokaryotic classification is now based primarily on DNA sequence data?

Accepted Answer

Morphological and biochemical features do not always reflect evolutionary history.

Chapter 20: The Diversity of Prokaryotes and Viruses – Study Notes

Study Guide - Practice Questions

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