Question 1

Which of the following best describes the defensive strategy of endospore formation in bacteria such as Bacillus and Clostridium?

Accepted Answer

Endospores enable bacteria to survive unfavorable environmental conditions by entering a dormant state.

Question 2

Which of the following is NOT a typical shape observed in prokaryotic cells?

Accepted Answer

Cuboidal

Question 3

A microbiologist observes a chain of spherical bacteria under the microscope. Which arrangement and division plane is most likely responsible for this observation?

Accepted Answer

Division in a single plane with incomplete separation

Question 4

Which of the following statements about archaea is TRUE?

Accepted Answer

Archaea have cell membrane lipids with branched hydrocarbon chains.

Question 5

Which group of bacteria is believed to have played a major role in transforming Earth's early anaerobic atmosphere into an oxygen-containing atmosphere?

Accepted Answer

Cyanobacteria

Question 6

A patient is diagnosed with a disease caused by a Gram-negative, intracellular pathogen transmitted by arthropod bites. Which genus is most likely responsible?

Accepted Answer

Rickettsia

Question 7

Which of the following best explains why binary fission can result in different arrangements of cocci (chains vs. clusters)?

Accepted Answer

The planes in which cells divide and whether daughter cells separate

Question 8

Which of the following equations correctly represents the process of methanogenesis by methanogenic archaea?

Accepted Answer

$$\mathrm{CO_2$ + 4H_2 \rightarrow CH_4$ + 2H_2O}$$

Question 9

Which of the following is a distinguishing feature of Mycoplasmas among the low G + C Gram-positive bacteria?

Accepted Answer

They lack a cell wall.

Question 10

A scientist isolates a bacterium from a hot spring that grows optimally at 90°C and has cell membrane lipids with branched hydrocarbon chains. To which group does this organism most likely belong?

Accepted Answer

Thermophilic archaea

Question 11

Which of the following best describes the ecological role of Nitrobacter in the nitrogen cycle?

Accepted Answer

It oxidizes nitrite to nitrate.

Question 12

Which of the following is a correct statement about the reproduction of Epulopiscium?

Accepted Answer

It reproduces viviparously, releasing live offspring from the mother cell.

Question 13

Which of the following is a reason why archaea are not known to cause disease in humans, plants, or animals?

Accepted Answer

They lack the necessary virulence factors to infect eukaryotic hosts.

Question 14

Which of the following best describes the function of the Bt toxin produced by Bacillus thuringiensis?

Accepted Answer

It is used as an insecticide in agriculture.

Question 15

Which of the following is a unique feature of the cell membrane of archaea compared to bacteria?

Accepted Answer

Presence of branched hydrocarbon chains

Question 16

Which of the following best explains why bacteria with widely divergent oxygen tolerances, sizes, shapes, and nutritional requirements are all classified in the same domain (Bacteria)?

Accepted Answer

They all share a common ancestor based on rRNA sequence analysis.

Question 17

Which of the following is a correct pairing of a phototrophic bacterial group and its main photosynthetic pigment?

Accepted Answer

Purple sulfur bacteria – Bacteriochlorophylls

Question 18

A patient with cystic fibrosis develops a respiratory infection with a Gram-negative bacterium that colonizes moist surfaces. Which genus is most likely responsible?

Accepted Answer

Burkholderia

Question 19

Which of the following equations represents the oxidation of methane by methane-oxidizing bacteria?

Accepted Answer

$$\mathrm{CH_4$ + 2O_2 \rightarrow CO_2$ + 2H_2O}$$

Question 20

Which of the following genera is most important in the formation of root nodules and nitrogen fixation in legumes?

Accepted Answer

Rhizobium

Characterizing and Classifying Prokaryotes: Structured Study Notes

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