Question 1

Which structural feature is unique to the cell walls of bacteria, distinguishing them from Archaea and Eukarya?

Accepted Answer

Presence of peptidoglycan

Question 2

A patient is infected with a bacterium that is resistant to penicillin. Which cellular structure is most likely altered in this bacterium to confer resistance?

Accepted Answer

Peptidoglycan layer

Question 3

Which process allows prokaryotes to exchange genetic material through direct cell-to-cell contact, often involving a pilus?

Accepted Answer

Conjugation

Question 4

What is the primary ecological role of chemoheterotrophic prokaryotes in the biosphere?

Accepted Answer

Decomposition and recycling of organic matter

Question 5

Which equation best represents the process of nitrogen fixation carried out by certain prokaryotes?

Accepted Answer

$$\mathrm{N_2$ + 8H^+ + 8e^- \rightarrow 2NH_3 + H_2$}$$

Question 6

Which group of bacteria is most closely associated with the origin of mitochondria according to the endosymbiotic theory?

Accepted Answer

Alpha Proteobacteria

Question 7

A bacterium is classified as a photoheterotroph. Which of the following best describes its energy and carbon sources?

Accepted Answer

Energy from light; carbon from organic compounds

Question 8

Which adaptation allows prokaryotes to survive harsh environmental conditions such as extreme heat or desiccation?

Accepted Answer

Formation of endospores

Question 9

Gram-negative bacteria differ from Gram-positive bacteria in which of the following ways?

Accepted Answer

They have an outer membrane containing lipopolysaccharides

Question 10

Which metabolic strategy is used by methanogens, a group of Archaea, in anaerobic environments?

Accepted Answer

Production of methane ($$\mathrm{CH_4$}) $$from carbon dioxide and hydrogen

Question 11

A researcher discovers a prokaryote living in a hot spring at 90°C. Which domain is this organism most likely to belong to?

Accepted Answer

Archaea

Question 12

Which of the following best explains why prokaryotes can adapt rapidly to environmental changes?

Accepted Answer

Short generation times and high rates of genetic recombination

Question 13

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

Accepted Answer

Cyanobacteria forming heterocysts for nitrogen fixation

Question 14

Which of the following is NOT a mechanism by which antibiotic resistance can spread among bacterial populations?

Accepted Answer

Photosynthesis

Question 15

Which type of symbiotic relationship is exemplified by gut bacteria that help humans digest food while benefiting from a stable environment?

Accepted Answer

Mutualism

Question 16

A Gram stain is performed on a bacterial sample. The bacteria appear purple under the microscope. What does this indicate about their cell wall structure?

Accepted Answer

They have a thick peptidoglycan layer (Gram-positive)

Question 17

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

Accepted Answer

A single circular chromosome located in the nucleoid

Question 18

Which of the following is a major reason why horizontal gene transfer is significant in prokaryotic evolution?

Accepted Answer

It allows rapid spread of advantageous traits such as antibiotic resistance

Question 19

Which of the following is a pathogenic bacterium responsible for causing Lyme disease?

Accepted Answer

Borrelia burgdorferi

Question 20

Which of the following best describes the role of prokaryotes in bioremediation?

Accepted Answer

They are used to break down pollutants in the environment

Bacteria and Archaea: Structure, Diversity, and Roles in Biology

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