Question 1

Which of the following statements best explains why most bacteria have not been characterized?

Accepted Answer

Many bacteria cannot be cultured in the laboratory, making them difficult to study.

Question 2

Which feature distinguishes most bacteria from archaea and eukaryotes?

Accepted Answer

Cell wall composed of peptidoglycan

Question 3

Why is the similarity between eukaryotic microbes (such as fungi) and humans problematic for medical treatment?

Accepted Answer

Drugs targeting fungi may also harm human cells due to shared cellular machinery.

Question 4

Which of the following is a unique characteristic of cyanobacteria?

Accepted Answer

They are the only oxygenic phototrophic prokaryotes.

Question 5

A researcher isolates a bacterium that forms heat-resistant endospores and produces toxins causing gangrene. To which group does this bacterium most likely belong?

Accepted Answer

Firmicutes

Question 6

Which of the following best describes the metabolic diversity of Proteobacteria?

Accepted Answer

They include photoheterotrophs, lithotrophs, and pathogens.

Question 7

Which equation best represents the oxygenic photosynthesis carried out by cyanobacteria?

Accepted Answer

$$6CO_2 + 6H_2O + light \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 8

Which group of bacteria is known for having a high mutation rate and sharing traits with archaea due to horizontal gene transfer?

Accepted Answer

Deep-branching thermophiles

Question 9

A patient is diagnosed with tuberculosis. Which bacterial group is the causative agent most likely from?

Accepted Answer

Actinobacteria

Question 10

Which of the following best explains why archaea are considered the most ecologically diverse domain?

Accepted Answer

They grow at a wider range of pH, temperature, and salt concentrations than bacteria or eukaryotes.

Question 11

Which of the following is a defining feature of Gram-negative bacteria?

Accepted Answer

A triple-layered cell envelope consisting of cell wall, periplasm, and cell membrane

Question 12

Which of the following best describes the role of Bacteroidetes in the human body?

Accepted Answer

They are major inhabitants of the human colon.

Question 13

Which of the following is true about Deinococcus radiodurans?

Accepted Answer

It resists extremely high doses of radiation and desiccation.

Question 14

Which of the following best describes the evolutionary significance of mitochondria?

Accepted Answer

They evolved from alphaproteobacteria through endosymbiosis.

Question 15

Which of the following is a characteristic of Mollicutes (such as Mycoplasma)?

Accepted Answer

They lack a cell wall and S-layer.

Question 16

Which of the following best explains why sequencing environmental samples is important for microbiology?

Accepted Answer

It allows for the identification of uncultured and unclassified bacteria.

Question 17

Which of the following is a function of heterocysts in cyanobacteria?

Accepted Answer

Nitrogen fixation

Question 18

Which of the following best describes the metabolic strategy of Chloroflexi?

Accepted Answer

Photoheterotrophs that are moderately thermophilic

Question 19

Which of the following is a common feature of Actinobacteria?

Accepted Answer

They form mycelia and produce antibiotics.

Question 20

Which of the following best describes the ecological role of Acidobacteria?

Accepted Answer

Many species live in extreme conditions.

Micro: lecture 3: 1/16

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