BIO 261 - Exam 3 - Penny Powell
Questions with Guaranteed Pass
Solutions 2025-2026 Updated.
-consists of the stomach, small intestine, and large intestine.
-responsible for digestion of food, absorption of nutrients, and production of nutrients by the
indigenous microbial flora. - Answer GI tract
prevents many organisms from colonizing the GI tract - Answer the acidity of the stomach
and the duodenum of the small intestine (pH 2)
common in the gastric fluid - Answer firmicutes, bacteroidetes, and actinobacteria
common in the mucus layer of the stomach - Answer firmicutes and proteobacteria
when present, found in the gastric mucosa - Answer helicobacter pylori
carry out a variety of essential metabolic reactions that produce various compounds - Answer
intestinal microorganisms
-essentially an in vivo fermentation vessel, with microbiota using nutrients derived from the
digestion of food
-most organisms are restricted to the lumen, while others are in the mucosal layer - Answer
the large intestine/colon
many microbial metabolites or transformation products that can be generated in the gut have
significant influence on host physiology, such as - Answer vitamin production, modification
of steroids, and amino acid biosynthesis
a complex, heterogeneous microbial habitat - Answer oral cavity
contains antimicrobial enzymes - Answer saliva
promote localized microbial growth in the mouth - Answer high concentrations of nutrients
near surfaces in the mouth
-mineral matrix in the tooth
,-surrounds living tissue, dentin, and pulp - Answer enamel
microbes thrive in the - Answer upper respiratory tract
bacteria continually enter the upper respiratory tract from - Answer the air during breathing
most bacteria that enter the upper respiratory tract are trapped in the ___ and expelled with
nasal secretions or swallowed and then killed in the stomach - Answer mucus of the nasal
and oral passages
the lower respiratory tract has no normal microbiota in healthy adults because ____ move
particles up and out of the lungs - Answer ciliated mucosal cells
altered conditions can cause potential pathogens in the urethra to - Answer multiply and
cause disease
frequently cause urinary tract infections in women - Answer E. coli and P. mirabilis
the vagina of the adult female is ___ and contains significant amounts of ___ - Answer
weakly acidic; glycogen
-a resident organism in the vagina
-ferments glycogen in the vagina, producing lactic acid - Answer Lactobacillus acidophilus
maintains a local acidic environment - Answer lactic acid
varies greatly in chemical composition and moisture content - Answer skin surface
three microenvironments of the skin - Answer dry skin, moist skin, and sebaceous skin
composition of microbes on the skin is influenced by - Answer environmental factors
(weather), host factors (puberty and personal hygiene), and each environment shows a unique
microbiota
-a biofilm formed by cells
-has Streptococcus and other fermenting bacteria that produce acid - Answer dental plaque
,the acid produced by fermenters - Answer wear down the tooth enamel
thought to contribute to several systemic conditions, including cardiovascular disease and
arthritis - Answer periodontal disease
oral antibiotics decrease ALL microbes in the human gut, both - Answer target and non
target
-a spore former
-antibiotic resistant
-infections are associated with antibiotic use - Answer clostridium difficile
-antibiotic that kills gram negative and gram positive bacteria
-causes diarrhea - Answer broad spectrum
contains live bacteria (yogurt) - Answer active culture
___ and ___ have active cultures - Answer lactobacillus and streptococcus
antibiotic that kills gram negative or gram positive bacteria, but not both - Answer narrow
spectrum
block pathogens from adhering to the host - Answer normal flora bacteria
-spore formers
-gram positive rods
-anaerobic - Answer clostridium
live organisms that confer a health benefit to the host - Answer probiotics
-commonly used in probiotics
-found in yogurt and probiotic drinks
-may work by taking up space or nutrients, limiting the ability of pathogens to colonize the gut -
Answer bifidobacterium and lactobacillus
, carbohydrates that are indigestible by human hosts, but provide nutrition for fermentative gut
bacteria - Answer prebiotics
situation in which a microorganism is established and growing in a host, whether or not the host
is harmed - Answer infection
microbial parasites that cause disease or tissue damage in a host - Answer pathogens
-the enhanced ability of microbes to attach to host tissues
-it is necessary, but not sufficient, to start disease - Answer adherence
-prevent phagocytosis
-made out of polysaccharides like ours, so the phagocyte doesn't recognize it as foreign, so it
isn't phagocytized - Answer capsule
cause tissue damage - Answer toxins
toxins that lyse RBCs - Answer hemolysins
-produces leukocidins
-causes strep throat - Answer streptococcus pyogenes
partially lyse RBCs - Answer alpha (A) hemolysins
completely lyses RBCs - Answer beta (B) hemolysins
do not lyse RBCs - Answer gamma (G) hemolysins
-breaks down host tissues
-allows bacteria to spread throughout the inside of the body where there is more nutrients and
no competition, so the pathogen can grow and cause an infection, eventually causing a disease -
Answer hyaluronidase
helps protect the skin - Answer collagen
breaks down collagen - Answer collagenase
Questions with Guaranteed Pass
Solutions 2025-2026 Updated.
-consists of the stomach, small intestine, and large intestine.
-responsible for digestion of food, absorption of nutrients, and production of nutrients by the
indigenous microbial flora. - Answer GI tract
prevents many organisms from colonizing the GI tract - Answer the acidity of the stomach
and the duodenum of the small intestine (pH 2)
common in the gastric fluid - Answer firmicutes, bacteroidetes, and actinobacteria
common in the mucus layer of the stomach - Answer firmicutes and proteobacteria
when present, found in the gastric mucosa - Answer helicobacter pylori
carry out a variety of essential metabolic reactions that produce various compounds - Answer
intestinal microorganisms
-essentially an in vivo fermentation vessel, with microbiota using nutrients derived from the
digestion of food
-most organisms are restricted to the lumen, while others are in the mucosal layer - Answer
the large intestine/colon
many microbial metabolites or transformation products that can be generated in the gut have
significant influence on host physiology, such as - Answer vitamin production, modification
of steroids, and amino acid biosynthesis
a complex, heterogeneous microbial habitat - Answer oral cavity
contains antimicrobial enzymes - Answer saliva
promote localized microbial growth in the mouth - Answer high concentrations of nutrients
near surfaces in the mouth
-mineral matrix in the tooth
,-surrounds living tissue, dentin, and pulp - Answer enamel
microbes thrive in the - Answer upper respiratory tract
bacteria continually enter the upper respiratory tract from - Answer the air during breathing
most bacteria that enter the upper respiratory tract are trapped in the ___ and expelled with
nasal secretions or swallowed and then killed in the stomach - Answer mucus of the nasal
and oral passages
the lower respiratory tract has no normal microbiota in healthy adults because ____ move
particles up and out of the lungs - Answer ciliated mucosal cells
altered conditions can cause potential pathogens in the urethra to - Answer multiply and
cause disease
frequently cause urinary tract infections in women - Answer E. coli and P. mirabilis
the vagina of the adult female is ___ and contains significant amounts of ___ - Answer
weakly acidic; glycogen
-a resident organism in the vagina
-ferments glycogen in the vagina, producing lactic acid - Answer Lactobacillus acidophilus
maintains a local acidic environment - Answer lactic acid
varies greatly in chemical composition and moisture content - Answer skin surface
three microenvironments of the skin - Answer dry skin, moist skin, and sebaceous skin
composition of microbes on the skin is influenced by - Answer environmental factors
(weather), host factors (puberty and personal hygiene), and each environment shows a unique
microbiota
-a biofilm formed by cells
-has Streptococcus and other fermenting bacteria that produce acid - Answer dental plaque
,the acid produced by fermenters - Answer wear down the tooth enamel
thought to contribute to several systemic conditions, including cardiovascular disease and
arthritis - Answer periodontal disease
oral antibiotics decrease ALL microbes in the human gut, both - Answer target and non
target
-a spore former
-antibiotic resistant
-infections are associated with antibiotic use - Answer clostridium difficile
-antibiotic that kills gram negative and gram positive bacteria
-causes diarrhea - Answer broad spectrum
contains live bacteria (yogurt) - Answer active culture
___ and ___ have active cultures - Answer lactobacillus and streptococcus
antibiotic that kills gram negative or gram positive bacteria, but not both - Answer narrow
spectrum
block pathogens from adhering to the host - Answer normal flora bacteria
-spore formers
-gram positive rods
-anaerobic - Answer clostridium
live organisms that confer a health benefit to the host - Answer probiotics
-commonly used in probiotics
-found in yogurt and probiotic drinks
-may work by taking up space or nutrients, limiting the ability of pathogens to colonize the gut -
Answer bifidobacterium and lactobacillus
, carbohydrates that are indigestible by human hosts, but provide nutrition for fermentative gut
bacteria - Answer prebiotics
situation in which a microorganism is established and growing in a host, whether or not the host
is harmed - Answer infection
microbial parasites that cause disease or tissue damage in a host - Answer pathogens
-the enhanced ability of microbes to attach to host tissues
-it is necessary, but not sufficient, to start disease - Answer adherence
-prevent phagocytosis
-made out of polysaccharides like ours, so the phagocyte doesn't recognize it as foreign, so it
isn't phagocytized - Answer capsule
cause tissue damage - Answer toxins
toxins that lyse RBCs - Answer hemolysins
-produces leukocidins
-causes strep throat - Answer streptococcus pyogenes
partially lyse RBCs - Answer alpha (A) hemolysins
completely lyses RBCs - Answer beta (B) hemolysins
do not lyse RBCs - Answer gamma (G) hemolysins
-breaks down host tissues
-allows bacteria to spread throughout the inside of the body where there is more nutrients and
no competition, so the pathogen can grow and cause an infection, eventually causing a disease -
Answer hyaluronidase
helps protect the skin - Answer collagen
breaks down collagen - Answer collagenase
