Question 1

Which of the following best describes the difference between 'microbiome' and 'microbiota' in the context of human health?

Accepted Answer

Microbiome is the functional collection of different microbes in a particular system, while microbiota refers to the types of organisms present in a habitat.

Question 2

Which methodology has played a major role in identifying the diversity and abundance of different groups within the human microbiome?

Accepted Answer

Metagenomics

Question 3

In the large intestine, most microorganisms are restricted to which anatomical location?

Accepted Answer

The lumen

Question 4

Which of the following is a major product of intestinal microbiota that contributes to the 'education' of the immune system?

Accepted Answer

Short-chain fatty acids (SCFAs) such as acetate and butyrate

Question 5

Why do breastfed infants develop a different gut microbiome compared to formula-fed infants?

Accepted Answer

Breast milk contains unique oligosaccharides that promote the growth of specific gut bacteria.

Question 6

Which bacterial genus is most abundant in the gastrointestinal tract according to the overview of the human microbiome?

Accepted Answer

Bacteroides

Question 7

A patient develops a urinary tract infection after a change in urine pH. Which of the following bacteria is most likely responsible?

Accepted Answer

Escherichia coli

Question 8

Which process is responsible for maintaining the acidic environment of the adult female vagina?

Accepted Answer

Fermentation of glycogen by Lactobacillus acidophilus producing lactic acid

Question 9

Which factor does NOT influence the composition of the skin microbiota?

Accepted Answer

Dietary fiber intake

Question 10

What is the primary reason the lower respiratory tract does not have a naturally resident microbiota?

Accepted Answer

Microbes are trapped in mucus and expelled or killed in the stomach.

Question 11

Which of the following statements about Inflammatory Bowel Disease (IBD) is correct?

Accepted Answer

Antibiotic use in early life increases the risk of developing IBD.

Question 12

Obese humans tend to have higher levels of which microbial groups in their gut compared to lean humans?

Accepted Answer

Methanogens and Prevotella

Question 13

Which of the following best explains the mechanism by which fermenting bacteria in dental biofilms contribute to dental caries?

Accepted Answer

They produce acid that demineralizes tooth enamel.

Question 14

What is the main risk associated with oral antibiotic use in the first few months of life?

Accepted Answer

Increased risk of developing IBD and other disorders related to dysbiosis

Question 15

Fecal transplants are most effective in treating which of the following infections?

Accepted Answer

Clostridioides difficile

Question 16

Which of the following is a common probiotic bacterium found in commercial products?

Accepted Answer

Lactobacillus acidophilus

Question 17

Prebiotics are best described as:

Accepted Answer

Carbohydrates indigestible by humans but provide nutrition for fermentative gut bacteria

Question 18

Which equation best represents the production of lactic acid by Lactobacillus acidophilus in the vagina?

Accepted Answer

$$\mathrm{C_6H_{10}O_5$} + H_2O \rightarrow 2 \mathrm{C_3H_6O_3}$$

Question 19

Which of the following is a plausible consequence of reduced gut microbiome diversity due to early antibiotic use?

Accepted Answer

Increased risk of chronic inflammatory diseases such as IBD

Question 20

Which multi-step process best describes metagenomic analysis of the human microbiome?

Accepted Answer

Sample collection → DNA extraction → DNA library preparation → DNA sequencing → Sequence analysis and reconstruction

Microbial Symbioses with Humans: The Human Microbiome and Its Impact

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