Microbiology Lab 8 Questions with Correct Answers | Updated (100% Correct Answers)

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Microbiology Lab 8 Questions with Correct
Answers | Updated (100% Correct Answers)
GI bacteria Answer: • the stomach and small intestine contain
relatively few bacteria

• the large intestine bacterial populations are significant

why does the stomach and small intestine contain relatively few
bacteria? Answer: • HCl produced by the stomach is unbearable for
most bacteria

• rapid movement of food through the small intestine prevents
attachement (peristalsis)

large intestine bacteria Answer: • primarily in the colon

• up to 10^11 bacteria per gram of feces

• most are commensals

commensal bacteria in feces Answer: • mutualistic relationship with
host

• make us vitamin K and folic acid

gastrointestinal diseases Answer: • most GI diseases result from the
ingestion of contaminated food or water


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• prevented by good sanitation/hygiene practices

problem with GI diseases Answer: • separating and identifying the
normal inhabitants from the pathogens

• large intestine consists primarily of anaerobes

• most fecal contamination is associated with gram negative
facultative anaerobes

upper GI Answer: • stomach and duodenum

• biopsy

lower GI Answer: • small and large intestine

• stool

• rectal swab

• sometimes blood cultures

stool Answer: • requires selective and differential media

• Salmonella and Shigella spp. may require enrichment media

typhoid fever Answer: results from Salmonella infection

MAC agar Answer: • MacConkey Agar




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