Question 1

Which of the following best describes the difference between the terms 'microbiota' and 'microbiome' as used in microbiology?

Accepted Answer

Microbiota refers to the microbial taxa associated with humans, while microbiome refers to the catalog of these microbes and their genes.

Question 2

Which of the following is a defining characteristic of a holobiont?

Accepted Answer

It refers to the host and all associated organisms, including virome, microbiome, and other symbionts, that function together.

Question 3

What is the primary method used to classify bacteria into Operational Taxonomic Units (OTUs)?

Accepted Answer

By comparing the sequence similarity of the 16S rRNA gene at a threshold of 97% or above.

Question 4

Which of the following statements about the development of the human microbiome is correct?

Accepted Answer

A stable, adult-like microbiome is typically developed by age 3.

Question 5

Bifidobacteria are important in the infant gut microbiome because they:

Accepted Answer

Can synthesize all amino acids and growth factors from simple carbohydrates, ferment sugars to provide calories, and lower gut pH to limit pathogen growth.

Question 6

Which of the following is NOT a major phylum commonly found in the adult human microbiota?

Accepted Answer

Cyanobacteria

Question 7

Why is the skin considered an inhospitable environment for many microbes?

Accepted Answer

It is slightly acidic, has high NaCl concentration, and many areas are low in moisture.

Question 8

Cutibacterium acnes is associated with which skin condition, and what is its role?

Accepted Answer

Acne vulgaris; it degrades sebum lipids, producing fatty acids that may contribute to inflammation.

Question 9

Which of the following statements about the gut microbiome and metabolism is supported by research?

Accepted Answer

Gut bacteria ferment complex polysaccharides into short-chain fatty acids, some of which promote weight gain.

Question 10

Which of the following is NOT a route by which the gut microbiome can communicate with the central nervous system (CNS)?

Accepted Answer

By direct migration of bacteria into the brain tissue.

Question 11

A patient is diagnosed with metabolic syndrome. Which of the following is NOT a diagnostic criterion for this condition?

Accepted Answer

Low fasting blood glucose levels

Question 12

Metabolic endotoxemia is characterized by which of the following?

Accepted Answer

A persistent, low-grade inflammation due to increased circulating endotoxins such as bacterial lipopolysaccharide (LPS).

Question 13

Which of the following best describes a probiotic?

Accepted Answer

A live microorganism that, when administered in adequate amounts, confers a health benefit to the host.

Question 14

A germ-free (GF) mouse is given a fecal microbiome transplant from an obese mouse. What is the most likely outcome?

Accepted Answer

The GF mouse will become obese, even without changes to diet or exercise.

Question 15

Which of the following body sites is normally free of microorganisms in healthy individuals?

Accepted Answer

Kidneys

Question 16

Which of the following best explains why some microbes can survive passage through the stomach?

Accepted Answer

They are resistant to gastric pH or pass through the stomach quickly, sometimes protected by food particles.

Question 17

Which of the following is a plausible consequence of loss of microbiome diversity (dysbiosis)?

Accepted Answer

Increased risk of diseases involving inflammation, such as inflammatory bowel disease and metabolic syndrome.

Question 18

Which of the following is a function of the functional core microbiome?

Accepted Answer

Production of vitamin K by Escherichia coli.

Question 19

Which of the following best describes a synbiotic?

Accepted Answer

A food or supplement that contains both a prebiotic and a probiotic.

Question 20

Which of the following genera is considered part of the core microbiome in the large intestine of people living in industrialized nations?

Accepted Answer

Bacteroides

Microbe-Human Ecosystem: The Human Microbiome and Its Role in Health

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