Question 1

Which of the following statements best explains why prokaryotes are considered essential to life on Earth?

Accepted Answer

They recycle carbon and other chemical elements between organic matter and the environment.

Question 2

Which structure allows prokaryotes to adhere to surfaces and to each other, playing a key role in the formation of biofilms?

Accepted Answer

Fimbriae (attachment pili)

Question 3

A bacterium is found to have a thick peptidoglycan layer and no outer membrane. Which Gram stain result and classification would you expect?

Accepted Answer

Gram-positive; stains purple

Question 4

Which metabolic category describes an organism that uses light for energy and CO$$_2 as a $$carbon source?

Accepted Answer

Photoautotroph

Question 5

Which process involves the direct transfer of genetic material between two prokaryotic cells via a sex pilus?

Accepted Answer

Conjugation

Question 6

A scientist discovers a prokaryote living in a hot spring with a cell wall lacking peptidoglycan. To which domain does this organism most likely belong?

Accepted Answer

Archaea

Question 7

Which of the following best describes the genetic material of most prokaryotes?

Accepted Answer

A single circular DNA molecule located in the nucleoid region

Question 8

Which of the following is a real-world example of a beneficial symbiotic relationship involving prokaryotes?

Accepted Answer

Bacteria in the human intestine producing vitamins

Question 9

A bacterium is classified as a chemoheterotroph. Which of the following best describes its nutritional requirements?

Accepted Answer

It uses organic molecules for both energy and carbon.

Question 10

Which of the following mechanisms is responsible for the high genetic diversity observed in prokaryotic populations?

Accepted Answer

Frequent mutations during rapid binary fission

Question 11

Which of the following best explains why antibiotics that target peptidoglycan synthesis are effective against many bacteria but not archaea?

Accepted Answer

Archaea have cell walls composed of polysaccharides and proteins, not peptidoglycan.

Question 12

Which of the following is NOT a mechanism by which prokaryotes can exchange genetic material?

Accepted Answer

Binary fission

Question 13

A patient is infected with a bacterium that can survive only in the absence of oxygen. Which term best describes this bacterium?

Accepted Answer

Obligate anaerobe

Question 14

Which of the following best describes the evolutionary origin of mitochondria and chloroplasts in eukaryotic cells?

Accepted Answer

They evolved from prokaryotes that became endosymbionts within larger host cells.

Question 15

Which of the following is a distinguishing feature of Gram-negative bacteria compared to Gram-positive bacteria?

Accepted Answer

Presence of an outer membrane containing lipopolysaccharides

Question 16

Which group of bacteria is responsible for generating oxygen through photosynthesis and is thought to be the ancestor of plant chloroplasts?

Accepted Answer

Cyanobacteria

Question 17

A soil bacterium is found to fix atmospheric nitrogen in association with legume roots. Which genus is most likely responsible for this process?

Accepted Answer

Rhizobium

Question 18

Which of the following best describes the function of plasmids in prokaryotes?

Accepted Answer

They provide genes for resistance to antibiotics and other special functions.

Question 19

Which of the following scenarios best illustrates the process of transduction in bacteria?

Accepted Answer

A virus transfers DNA from one bacterium to another.

Question 20

Which of the following is a correct statement about the diversity of prokaryotes?

Accepted Answer

Prokaryotes are divided into two major domains: Bacteria and Archaea.

Bacteria and Archaea: Structure, Function, and Diversity of Prokaryotes

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