Question 1

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

Accepted Answer

Gram-negative bacteria possess an outer membrane containing lipopolysaccharides that restricts antibiotic access.

Question 2

A researcher discovers a prokaryote that can survive in extremely salty environments and produces methane as a metabolic by-product. To which group does this organism most likely belong?

Accepted Answer

Methanogenic archaea

Question 3

Which structure allows prokaryotes to adhere to surfaces and evade a host's immune system, and what is it called when this structure is dense and well-defined?

Accepted Answer

Capsule; capsule

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, and how can it spread to other bacteria?

Accepted Answer

R plasmid; by conjugation

Question 5

Which of the following best describes the process of nitrogen fixation in prokaryotes?

Accepted Answer

Conversion of atmospheric nitrogen ($$N_2) to $$ammonia ($$NH_3)$$

Question 6

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

Accepted Answer

The evolution of bacterial flagella from proteins originally used in a secretory system

Question 7

A nonpathogenic bacterium acquires the ability to cause disease after taking up DNA from its environment. Which process is responsible for this genetic change?

Accepted Answer

Transformation

Question 8

Which metabolic strategy would you expect to find in a prokaryote living in deep-sea hydrothermal vents, and what is the primary energy source?

Accepted Answer

Chemoautotrophy; inorganic chemicals

Question 9

Which of the following statements about prokaryotic reproduction and genetic diversity is correct?

Accepted Answer

Prokaryotes reproduce by binary fission, but genetic diversity arises through mutation and genetic recombination.

Question 10

A bacterium is found to have a thick peptidoglycan layer and no outer membrane. Which of the following is most likely true about this bacterium?

Accepted Answer

It is gram-positive and more susceptible to antibiotics targeting peptidoglycan.

Question 11

Which of the following best explains why salt is effective as a food preservative?

Accepted Answer

Salt creates a hypertonic environment, causing prokaryotes to lose water and slow reproduction.

Question 12

Which of the following is a real-world example of metabolic cooperation among prokaryotes?

Accepted Answer

Anabaena filaments with specialized heterocysts for nitrogen fixation and other cells for photosynthesis

Question 13

Which of the following best describes the role of prokaryotes in chemical recycling within ecosystems?

Accepted Answer

Prokaryotes decompose organic matter, releasing elements like carbon and nitrogen for reuse by other organisms.

Question 14

A patient develops food poisoning after eating undercooked eggs. The responsible bacterium is gram-negative and releases toxins only when it dies. Which type of toxin is involved?

Accepted Answer

Endotoxin

Question 15

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

Accepted Answer

It can result in the rapid spread of antibiotic resistance genes across different species.

Question 16

Which of the following best describes the nutritional mode of a bacterium that uses light for energy and organic compounds for its carbon source?

Accepted Answer

Photoheterotroph

Question 17

A hospital patient develops a chronic infection on a catheter that is resistant to antibiotics. Which prokaryotic adaptation is most likely responsible for the persistence of this infection?

Accepted Answer

Biofilm formation

Question 18

Which of the following is a correct pairing of a prokaryotic group and a disease it causes?

Accepted Answer

Spirochetes; Lyme disease

Question 19

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

Accepted Answer

It is a prokaryotic system that has been adapted for gene editing in research.

Question 20

Which of the following best explains why prokaryotes are considered essential for the survival of most ecosystems on Earth?

Accepted Answer

They play key roles in nutrient cycling, decomposition, and symbiotic relationships.

Prokaryotes: Structure, Diversity, and Roles in the Biosphere

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