Question 1

Which of the following best describes the concept of functional redundancy in a microbial community?

Accepted Answer

Different microbial species can perform the same ecological function, so the loss of one species may not disrupt the community's function.

Question 2

A researcher observes that after a short-term antibiotic treatment, a patient's gut microbiome returns to its original composition. Which ecological property does this illustrate?

Accepted Answer

Resilience

Question 3

Which of the following equations correctly represents the process of carbon fixation by photosynthetic microbes?

Accepted Answer

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

Question 4

Which scenario best exemplifies mutualism in microbial ecology?

Accepted Answer

A fungus and an alga form a lichen, where the fungus provides structure and the alga produces food.

Question 5

Which process in the nitrogen cycle is responsible for converting atmospheric nitrogen ($$N_2) $$into ammonia ($$NH_3) $$usable by plants?

Accepted Answer

Nitrogen fixation

Question 6

A microbial community in a freshwater lake is exposed to a pollutant. Species richness remains unchanged, but one species becomes dominant. Which metric has changed most?

Accepted Answer

Evenness

Question 7

Which of the following best describes a pulse disturbance in microbial ecology?

Accepted Answer

A short-term event such as a single dose of antibiotics that temporarily disrupts the microbial community.

Question 8

Which adaptation allows acidophilic microbes to survive in low pH environments?

Accepted Answer

Pumping excess protons out of their cells to maintain internal pH.

Question 9

A patient develops a Clostridioides difficile infection after antibiotic treatment. This is most directly due to the loss of:

Accepted Answer

Colonization resistance

Question 10

Which of the following is a real-world example of microbial succession?

Accepted Answer

After a forest fire, spore-forming bacteria colonize first, followed by nitrogen-fixing cyanobacteria, then diverse decomposers.

Question 11

Which of the following best describes the role of methanogenic microbes in the carbon cycle?

Accepted Answer

They produce methane ($$CH_4) $$from carbon compounds in oxygen-poor environments.

Question 12

Which evolutionary mechanism most rapidly spreads antibiotic resistance between unrelated bacterial species in the gut?

Accepted Answer

Horizontal gene transfer

Question 13

Which of the following is a direct product of gut microbial fermentation of dietary fiber that fuels colon epithelial cells?

Accepted Answer

Butyrate

Question 14

A microbial biofilm on a medical implant is highly resistant to antibiotics. What is the primary reason for this resistance?

Accepted Answer

Protective extracellular matrix and cooperative microbial interactions

Question 15

Which of the following best explains why a highly diverse gut microbiome reduces pathogen colonization?

Accepted Answer

Competitive exclusion

Question 16

Which process in the sulfur cycle is responsible for the production of hydrogen sulfide ($$H_2S) $$with a characteristic rotten egg smell?

Accepted Answer

Sulfate reduction

Question 17

A microbe that can switch between aerobic respiration, nitrate respiration, and fermentation depending on environmental conditions is best described as a:

Accepted Answer

Generalist

Question 18

Which of the following best describes the 'rare biosphere' in microbial ecology?

Accepted Answer

Rare microbial species present in low abundance that can rapidly grow and dominate when conditions change.

Question 19

Which of the following is a real-world example of a positive climate feedback loop involving microbes?

Accepted Answer

Permafrost thaw releases organic matter, microbes metabolize it to produce $$CO_2$$ and $$CH_4$$, accelerating global warming.

Question 20

Which of the following best describes the hygiene hypothesis in relation to the human microbiome?

Accepted Answer

Children exposed to a greater variety of microbes develop stronger immune systems.

lec 22:Microbial Ecology: Community Structure, Interactions, and Human Health

Study Guide - Practice Questions

Study Guide - Flashcards