Question 1

Which of the following processes is universal to all types of cells, regardless of domain?

Accepted Answer

DNA replication

Question 2

Epulopiscium and Thiomargarita are notable for their unusually large cell size. Which trait most directly enables them to overcome the limitations of diffusion in large cells?

Accepted Answer

Highly folded plasma membranes that increase surface area

Question 3

Which phylum of Archaea is most commonly found in soils and oceans worldwide, and what is a likely reason for its abundance?

Accepted Answer

Thaumarchaeota; because they are efficient ammonia oxidizers

Question 4

Why were cyanobacteria so important in the evolution of life on Earth?

Accepted Answer

They produced oxygen through photosynthesis, leading to the Great Oxidation Event

Question 5

A cow’s ability to digest cellulose is largely due to which microbial process?

Accepted Answer

Fermentation by gut bacteria producing cellulase

Question 6

Which of the following is NOT a way that microorganisms are important in the food and agriculture industries?

Accepted Answer

Increasing the shelf life of fresh produce through direct application

Question 7

Wastewater treatment is essential for which of the following reasons?

Accepted Answer

To remove organic matter and pathogens before water is released into the environment

Question 8

Koch’s postulates are a set of criteria designed to:

Accepted Answer

Establish a causal relationship between a microbe and a specific disease

Question 9

A researcher isolates a new bacterium from soil that can oxidize ammonia. To which archaeal phylum is this process most closely related, and what is the chemical equation for ammonia oxidation?

Accepted Answer

Thaumarchaeota; $$\mathrm{NH_3$ + 1.5\ O_2$ \rightarrow NO_2$^- + H^+ + H_2O}$$

Question 10

Which of the following best explains why large prokaryotic cells like Epulopiscium can survive despite the limitations of surface area to volume ratio?

Accepted Answer

They have multiple copies of their genome distributed throughout the cell

Question 11

Which of the following is a direct consequence of the Great Oxidation Event caused by cyanobacteria?

Accepted Answer

The evolution of aerobic respiration

Question 12

A patient is diagnosed with a bacterial disease. According to Koch’s postulates, which step is necessary to confirm the causative agent?

Accepted Answer

The suspected pathogen must be isolated and grown in pure culture

Question 13

Which of the following best describes the role of microbes in the human gut?

Accepted Answer

They synthesize essential vitamins and aid in digestion

Question 14

Which of the following is a real-world example of microbial contribution to agriculture?

Accepted Answer

Rhizobium bacteria fixing atmospheric nitrogen in legume root nodules

Question 15

Which equation best represents the process of aerobic respiration, a universal process in many cells?

Accepted Answer

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

Question 16

A wastewater treatment plant uses microbial communities to break down organic matter. Which process is primarily responsible for reducing the biological oxygen demand (BOD) in the water?

Accepted Answer

Aerobic microbial respiration

Question 17

Which of the following scenarios would violate Koch’s postulates?

Accepted Answer

The suspected pathogen cannot be cultured in the laboratory

Question 18

Which of the following is a key reason why wastewater treatment is important for public health?

Accepted Answer

It prevents the spread of waterborne diseases by removing pathogens

Question 19

Which of the following best explains why Thaumarchaeota are abundant in marine and soil environments?

Accepted Answer

They efficiently oxidize ammonia, playing a major role in the nitrogen cycle

Question 20

Which of the following is a multi-step process involving both microbial and chemical reactions in the nitrogen cycle?

Accepted Answer

Nitrification: $$\mathrm{NH_3$ \xrightarrow{Nitrosomonas} NO_2$^- \xrightarrow{Nitrobacter} NO_3$^-}$$

Fundamental Concepts in Microbial Ecology and Microbiology: Chapter Sections 1.1-1.6 & 1.11-1.15

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