Question 1

Which of the following statements 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 that restricts the entry of many antibiotics and contains efflux pumps.

Question 2

A scientist discovers a unicellular organism living in a hot spring with a temperature above 90°C. The organism lacks peptidoglycan in its cell wall and can survive in highly acidic conditions. To which domain does this organism most likely belong?

Accepted Answer

Archaea

Question 3

Which of the following best describes the process of bacterial conjugation?

Accepted Answer

A donor bacterium transfers DNA to a recipient through a pilus, forming a temporary mating bridge.

Question 4

Which of the following is a correct match between bacterial shape and its description?

Accepted Answer

Spirillum – spiral-shaped

Question 5

A patient is infected with a bacterium that stains pink after a Gram stain procedure. Which of the following is most likely true about this bacterium?

Accepted Answer

It has a thin peptidoglycan layer and an outer membrane.

Question 6

Which of the following best explains why prokaryotes can evolve rapidly?

Accepted Answer

They reproduce asexually by binary fission, have short generation times, and accumulate mutations quickly.

Question 7

Which of the following is an example of metabolic cooperation in prokaryotes?

Accepted Answer

Cyanobacteria forming filamentous colonies where some cells fix nitrogen and others perform photosynthesis, exchanging nutrients.

Question 8

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are metabolically inactive structures that allow bacteria to survive extreme conditions for long periods.

Question 9

Which of the following best describes the function of bacterial flagella?

Accepted Answer

They are used for motility, allowing bacteria to move toward or away from stimuli (taxis).

Question 10

A bacterium is found to be an obligate anaerobe. Which of the following environments would be most suitable for its growth?

Accepted Answer

An environment with no oxygen, such as deep mud or the intestines

Question 11

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

Accepted Answer

Rhizobium bacteria fixing nitrogen in the root nodules of legume plants, benefiting both the plant and the bacteria

Question 12

Which of the following best describes the role of R plasmids in bacterial populations?

Accepted Answer

They carry genes for antibiotic resistance, allowing bacteria to survive in the presence of antibiotics.

Question 13

Which of the following is NOT a mechanism of horizontal gene transfer in bacteria?

Accepted Answer

Binary fission

Question 14

Which of the following statements about the structure of prokaryotic cells is correct?

Accepted Answer

Prokaryotic cells have circular chromosomes located in the nucleoid region.

Question 15

A researcher is studying a prokaryote that can use light as an energy source and CO$$_2 as a $$carbon source. Which nutritional category does this organism belong to?

Accepted Answer

Photoautotroph

Question 16

Which of the following best explains why antibiotics such as tetracycline and erythromycin can inhibit bacterial growth without harming human cells?

Accepted Answer

They bind to prokaryotic ribosomes, which are structurally different from eukaryotic ribosomes.

Question 17

Which of the following is a function of biofilms in prokaryotic communities?

Accepted Answer

They facilitate metabolic cooperation and protect prokaryotes from environmental stress.

Question 18

Which of the following is a correct statement about nitrogen fixation?

Accepted Answer

It is the conversion of atmospheric nitrogen (N$$_2) $$into ammonia (NH$$_3$$), which can be used to make amino acids and nucleic acids.

Question 19

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

Accepted Answer

The use of flagellar proteins, originally involved in other cellular functions, to form the bacterial flagellum.

Question 20

Which of the following best describes the ecological importance of prokaryotes?

Accepted Answer

They play a major role in recycling chemical elements and decomposing organic matter.

Prokaryotes: Structure, Diversity, and Ecological Roles

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