Question 1

Which of the following best describes the difference between species richness and species abundance in a microbial community, as illustrated in $$image_1$$?

Accepted Answer

Species richness refers to the number of different species present, while species abundance refers to the proportion of each species within the community.

Question 2

Fluorescent in situ Hybridization (FISH) is used to distinguish between microbial groups. Which molecule do the fluorescent oligonucleotides hybridize to?

Accepted Answer

rRNA in ribosomes

Question 3

In the nitrogen cycle, which reaction is catalyzed by Nitrosococcus oceani?

Accepted Answer

$$ \mathrm{NH_3$ + \frac{1}{2} O_2$ \rightarrow NO_2$^- + H_2O} $$

Question 4

Which technique combines FISH with microautoradiography to determine the ability of an organism to use a substrate?

Accepted Answer

MAR-FISH

Question 5

Microbial communities are organized into guilds. What is a guild in microbial ecology?

Accepted Answer

A group of metabolically related organisms

Question 6

Why isn’t a soil particle completely covered in microbial growth, making it slimy?

Accepted Answer

Suboptimal resources or growth conditions and uneven nutrient distribution limit microbial growth

Question 7

Which region of the soil is most active for microbial growth due to nutrient availability?

Accepted Answer

Rhizosphere

Question 8

What is the primary function of mycorrhizal fungi in plant roots?

Accepted Answer

Transfer inorganic nutrients from soil to plant

Question 9

Which type of mycorrhizae forms an extensive sheath around the outside of plant roots with little penetration into root tissue?

Accepted Answer

Ectomycorrhizae

Question 10

In freshwater lakes, which microbial mutualism involves consortia of Green sulfur bacteria and a flagellated rod-shaped bacterium?

Accepted Answer

Chlorochromatium aggregatum

Question 11

What happens to oxygen and organic carbon levels in a river after the input of organic-rich wastewater?

Accepted Answer

Oxygen decreases while organic carbon increases

Question 12

Which microorganism is the most abundant photosynthetic microbe in the ocean?

Accepted Answer

Prochlorococcus

Question 13

What is a piezophile?

Accepted Answer

A microorganism that grows best under high pressure

Question 14

Which chemolithotrophic reaction is performed by sulfate-reducing bacteria near deep-sea hydrothermal vents?

Accepted Answer

$$ \mathrm{H_2$ + SO_4$^{2-} \rightarrow H_2S} $$

Question 15

What is the main reason biofilms form on solid surfaces?

Accepted Answer

Biofilms provide defense, allow cells to stay in a favorable niche, and enable metabolic cooperation

Question 16

Which disease is commonly associated with biofilm formation in humans?

Accepted Answer

Cystic fibrosis

Question 17

In the squid-Allivibrio symbiosis, what is the role of bioluminescence produced by Aliivibrio fischeri?

Accepted Answer

Camouflages the squid from predators by mimicking moonlight

Question 18

How is bioluminescence regulated in Aliivibrio fischeri within the squid light organ?

Accepted Answer

By quorum sensing, specifically when AHL binds to LuxR and activates luxCDABE transcription

Question 19

Which molecule acts as a quorum sensing signal in Staphylococcus aureus?

Accepted Answer

Autoinducing Peptide-1 (AIP-1)

Question 20

Microbial mats are most commonly found in which type of environment?

Accepted Answer

Hypersaline or geothermal habitats

Microbial Ecology: Diversity, Interactions, and Environmental Roles

Study Guide - Practice Questions

Study Guide - Flashcards