Microbiology 4000 Exam 3 OSU Test
Questions with Quality Answers 2026-
2027 Updated.
Steps of innate defenses - Answer 1)block 2) detect 3) destroy
first line defenses that block entry - Answer -physical barriers (skin on outside, mucous
membranes on inside)
-chemical barriers (antimicrobial substances)
- normal microbiota/flora
Detection occurs with - Answer PRRs, pattern recognition receptors
Ways to destroy pathogen via innate immunity - Answer inflammation, phagocytosis, action
of complement proteins, interferon production, and fever
How skin is a good barrier - Answer -difficult to penetrate
-many later of epithelial cells
-outermost layer of skin is dead; microbes cant establish
- skin sloughs off and takes microbes with it
-salty: not much microbes are halotolerant
mucous membranes - Answer line the digestive, respiratory, and genitourinary tracts
-mucous is sticky, microbes get stuck
actions like coughing get them out
antimicrobial substances - Answer salt, lysozymes, peroxidase enzymes, lactoferrin,
AMPs(defensins)
salt - Answer accumulates from perspiration, protects skin because most microbes are not
halotolerant
lysozyme - Answer degrades peptidoglycan, are at entry points, found in saliva and tears
, peroxidase enzymes - Answer break down hydrogen peroxide and produce toxic forms of
oxygen
lactoferrin - Answer found in mucous, finds to iron, makes iron unavailable to microbes
AMPS - Answer (antimicrobial peptides)
found in white blood cells, punctures membrane-results in cell death
defensin is type of AMP
ways normal microbiota helps - Answer competitive exclusion, production of toxic
compounds, alteration of environment
competitive exclusion - Answer normal microbiota cover binding sites(pathogens need to
bind to establish), consuming nutrients pathogens need
production of toxic compounds - Answer propionbacterium degrade lipids and produce fatty
acids, e.coli in intestines synthesize colicins which is toxic against intestinal pathogens
alteration of environment - Answer lactobacillus in vagina produces low pH so that
pathogens cant survive
Disruption of normal microbiota can - Answer predispose a person to infections
ex: clostridium difficile intestine and candida albicans in vagina
who preforms detection? - Answer white blood cells
hematopoiesis - Answer making of blood cells
blood cells originate from - Answer hematopoietic stem cells that are in bone marrow
blood cells can - Answer move around body and travel through circulatory system, some
reside in tissues
erythrocytes - Answer red blood cells, do not play a role in immune system
megakaryocytes - Answer platelets, helps fight infection by forming blood clot
Questions with Quality Answers 2026-
2027 Updated.
Steps of innate defenses - Answer 1)block 2) detect 3) destroy
first line defenses that block entry - Answer -physical barriers (skin on outside, mucous
membranes on inside)
-chemical barriers (antimicrobial substances)
- normal microbiota/flora
Detection occurs with - Answer PRRs, pattern recognition receptors
Ways to destroy pathogen via innate immunity - Answer inflammation, phagocytosis, action
of complement proteins, interferon production, and fever
How skin is a good barrier - Answer -difficult to penetrate
-many later of epithelial cells
-outermost layer of skin is dead; microbes cant establish
- skin sloughs off and takes microbes with it
-salty: not much microbes are halotolerant
mucous membranes - Answer line the digestive, respiratory, and genitourinary tracts
-mucous is sticky, microbes get stuck
actions like coughing get them out
antimicrobial substances - Answer salt, lysozymes, peroxidase enzymes, lactoferrin,
AMPs(defensins)
salt - Answer accumulates from perspiration, protects skin because most microbes are not
halotolerant
lysozyme - Answer degrades peptidoglycan, are at entry points, found in saliva and tears
, peroxidase enzymes - Answer break down hydrogen peroxide and produce toxic forms of
oxygen
lactoferrin - Answer found in mucous, finds to iron, makes iron unavailable to microbes
AMPS - Answer (antimicrobial peptides)
found in white blood cells, punctures membrane-results in cell death
defensin is type of AMP
ways normal microbiota helps - Answer competitive exclusion, production of toxic
compounds, alteration of environment
competitive exclusion - Answer normal microbiota cover binding sites(pathogens need to
bind to establish), consuming nutrients pathogens need
production of toxic compounds - Answer propionbacterium degrade lipids and produce fatty
acids, e.coli in intestines synthesize colicins which is toxic against intestinal pathogens
alteration of environment - Answer lactobacillus in vagina produces low pH so that
pathogens cant survive
Disruption of normal microbiota can - Answer predispose a person to infections
ex: clostridium difficile intestine and candida albicans in vagina
who preforms detection? - Answer white blood cells
hematopoiesis - Answer making of blood cells
blood cells originate from - Answer hematopoietic stem cells that are in bone marrow
blood cells can - Answer move around body and travel through circulatory system, some
reside in tissues
erythrocytes - Answer red blood cells, do not play a role in immune system
megakaryocytes - Answer platelets, helps fight infection by forming blood clot
