The Large Intestine and Gut Bacteria

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What is the pH level of the stomach?

pH 1 to 3 (correct)

pH 9 to 10

pH 7

pH 6.8 to 8.6

What is the characteristic of the climax community in the human GI tract?

It is an ecosystem where the host physiology is not influenced

It is an ecosystem in which progression of species has stopped (correct)

It is an ecosystem where bacteria are absent

It is an ecosystem where bacteria outnumber host cells

What is the approximate number of CFU/g of aerobic gram positives in the stomach?

10^3-10^4 CFU/g

10^6-10^7 CFU/g

10^8-10^9 CFU/g

< 10^3 CFU/g (correct)

Which of the following bacteria is not commonly found in the small intestine?

Fusobacterium Signup and view all the answers

What is the main difference between indigenous bacteria and transient bacteria in the GI tract?

Indigenous bacteria colonize the host, while transient bacteria are just passing through Signup and view all the answers

What is the effect of dietary factors on the distribution of bacteria in the GI tract?

Dietary factors make surprisingly little difference in the distribution of bacteria in the GI tract Signup and view all the answers

What is a crucial factor that influences the colonization of the human GI tract?

Gastric acidity Signup and view all the answers

What is a potential benefit of probiotics in relation to lactose?

Increased ability to use lactose Signup and view all the answers

In which of the following systems can probiotics have an alternative application?

Oral cavity Signup and view all the answers

What is a characteristic that should be retained in probiotic strains?

Strain characteristics Signup and view all the answers

What is a benefit of using non-viable probiotics?

All of the above Signup and view all the answers

What is the primary mechanism by which probiotic bacteria are thought to give health benefits?

Improving the balance of bacteria in the intestines Signup and view all the answers

What is the primary function of the large intestine in the digestive system?

To extract additional nutrients from partially digested food and absorb water Signup and view all the answers

What type of bacteria are introduced to an infant's gut through breast-feeding?

Bifidobacteria Signup and view all the answers

What is the estimated number of bacterial cells present in the human body?

1013 to 1014 Signup and view all the answers

What is the role of microflora in the large intestine?

To provide new nutrient sources to cells lining the large intestine Signup and view all the answers

What is the purpose of probiotics in maintaining gut health?

To maintain the balance of the microbial community Signup and view all the answers

What percentage of bacteria in healthy humans is constituted by 30-40 species of bacteria?

99% Signup and view all the answers