MBIO 3401 Final | Helping You Pass With Confidence.
What is the definition of infection? - Answer: the entry and growth of a microorganism within a
host
What are the two possible outcomes of infection? - Answer: - disease: the microorganism
produces symptoms and causes damage
- colonizations: the microorganism persists without causing disease
What is the difference between primary pathogen and opportunistic pathogen? - Answer: -
primary pathogen: regularly causes disease is at least some individuals with normal defenses
- opportunistic pathogen: usually does not cause disease except in individuals with
compromised defenses
What is the definition of virulence? - Answer: the degree of pathogenicity
What is a virulence factor? - Answer: specific properties of a pathogen that promote infection
and disease
From an ecological perspective, what types of symbiotic associations between organisms can
occur, and what type does a pathogen-host interaction represent? - Answer: - mutualism: both
organisms benefit
- commensalism: one organism benefits and the other is not affected
- parasitism: one organism benefits at the expense of the other (pathogen-host interaction)
Why does infectious disease occur at all? - Answer: - microbial entry into the host
- microbial attachment to surface tissues
- microbial growth and spread within the host
- microbial exit from the host
What are the portals of entry into the host? - Answer: - respiratory tract
- GI tract
pg. 1 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
,- genitourinary tract
- skin wounds
- eye and ear
- placenta
How do microorganism attach to the surface tissues of the host? - Answer: pili and other (non-
pilus) adhesions
What three microbial activities do many virulence factors promote during growth and spread of
the microbe within the host? - Answer: - scavenge nutrients
- penetrate host tissues
- counter host defenses
What are the specific virulence factors discusses in lecture? - Answer: - capsule
- toxins (endotoxins and exotoxins)
- extracellular enzymes
What is the difference between endotoxins and exotoxins? - Answer: endotoxins are
lipopolysaccharide and exotoxins are soluble proteins, gram + do not make endotoxins
What are the five different types of exotoxins discussed in lecture? - Answer: - botulinum
neurotoxin: blocks neurotransmitter release
- cholera enterotoxin: promotes massive fluid loss from intenstinal epithelium
- diphtheria cytotoxin: kills cells by inactivating translation
- hemolysins: lyse red blood cells by forming pores in membranes
- leukocidins: lyse white blood cells by forming pores in membranes
What types of extracellular enzymes can be produced? - Answer: - hyaluronidase: degrades
hyaluronic acid
- collagenase: degrades collagen
- coagulase: promotes blood clot formation
- streptokinase: dissolve blood clots
pg. 2 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
,- IgA protease: cleaves IgA antibodies
What are the portals of exit from the host? - Answer: - respiratory tract
- GI tract
- genitourinary tract
- skin wounds
- eye and ear
- placenta
What are the major physical and chemical barriers to infection? - Answer: - tissue integrity
- flushing mechanisms
- antimicrobial substances
What are examples of antimicrobial substances produces by specific host cells and tissues? -
Answer: - cationic antimicrobial peptides
- antibacterial fatty acids in perspiration
- lysozyme in tears and saliva
- lactoferrin in tears, saliva and milk
- gastric acids in stomach
- bile salts in intestine
- antiviral proteins in tissues
- antimicrobial proteins in blood and lymph
- transferrin in blood and lymph
What are the major biological barriers to infection? - Answer: - genetic resistance
- normal microbiota
- phagocytosis
- inflammation
In what ways does the normal microbiota benefit the host? - Answer: - limiting nutrient
availability
pg. 3 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
, - preventing pathogen attachment to host cell surfaces
- synthesizing antimicrobial agents
- development of the immune system
- use of probiotics
What is the definition of phagocytosis? - Answer: to eat hallow vessel
What are the four steps of phagocytosis? - Answer: - chemotaxis
- attachment
- engulfment
- digestion
What are the three major types of cells in whole blood? - Answer: - erythrocytes
- leukocytes
- thrombocytes
What are the two major categories of leukocytes? - Answer: - granulocytes
- agranulocytes
How are the two categories of leukocytes further classifies according to their appearance in the
Wright stain? - Answer: - granulocytes: basophils, eosinophils, neutrophils
- agranulocytes: monocytes, lymphocytes
What is the fluid portion of blood called (a) before and (b) after the clotting factors are
removed? - Answer: (a): plasma
(b): serum
What is the inflammation response? - Answer: - damage to host tissues produces injured and
dead cells
- cells in damaged tissues release mediators
- tissue repair and regeneration occurs
- inflammation response is shut down
pg. 4 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
What is the definition of infection? - Answer: the entry and growth of a microorganism within a
host
What are the two possible outcomes of infection? - Answer: - disease: the microorganism
produces symptoms and causes damage
- colonizations: the microorganism persists without causing disease
What is the difference between primary pathogen and opportunistic pathogen? - Answer: -
primary pathogen: regularly causes disease is at least some individuals with normal defenses
- opportunistic pathogen: usually does not cause disease except in individuals with
compromised defenses
What is the definition of virulence? - Answer: the degree of pathogenicity
What is a virulence factor? - Answer: specific properties of a pathogen that promote infection
and disease
From an ecological perspective, what types of symbiotic associations between organisms can
occur, and what type does a pathogen-host interaction represent? - Answer: - mutualism: both
organisms benefit
- commensalism: one organism benefits and the other is not affected
- parasitism: one organism benefits at the expense of the other (pathogen-host interaction)
Why does infectious disease occur at all? - Answer: - microbial entry into the host
- microbial attachment to surface tissues
- microbial growth and spread within the host
- microbial exit from the host
What are the portals of entry into the host? - Answer: - respiratory tract
- GI tract
pg. 1 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
,- genitourinary tract
- skin wounds
- eye and ear
- placenta
How do microorganism attach to the surface tissues of the host? - Answer: pili and other (non-
pilus) adhesions
What three microbial activities do many virulence factors promote during growth and spread of
the microbe within the host? - Answer: - scavenge nutrients
- penetrate host tissues
- counter host defenses
What are the specific virulence factors discusses in lecture? - Answer: - capsule
- toxins (endotoxins and exotoxins)
- extracellular enzymes
What is the difference between endotoxins and exotoxins? - Answer: endotoxins are
lipopolysaccharide and exotoxins are soluble proteins, gram + do not make endotoxins
What are the five different types of exotoxins discussed in lecture? - Answer: - botulinum
neurotoxin: blocks neurotransmitter release
- cholera enterotoxin: promotes massive fluid loss from intenstinal epithelium
- diphtheria cytotoxin: kills cells by inactivating translation
- hemolysins: lyse red blood cells by forming pores in membranes
- leukocidins: lyse white blood cells by forming pores in membranes
What types of extracellular enzymes can be produced? - Answer: - hyaluronidase: degrades
hyaluronic acid
- collagenase: degrades collagen
- coagulase: promotes blood clot formation
- streptokinase: dissolve blood clots
pg. 2 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
,- IgA protease: cleaves IgA antibodies
What are the portals of exit from the host? - Answer: - respiratory tract
- GI tract
- genitourinary tract
- skin wounds
- eye and ear
- placenta
What are the major physical and chemical barriers to infection? - Answer: - tissue integrity
- flushing mechanisms
- antimicrobial substances
What are examples of antimicrobial substances produces by specific host cells and tissues? -
Answer: - cationic antimicrobial peptides
- antibacterial fatty acids in perspiration
- lysozyme in tears and saliva
- lactoferrin in tears, saliva and milk
- gastric acids in stomach
- bile salts in intestine
- antiviral proteins in tissues
- antimicrobial proteins in blood and lymph
- transferrin in blood and lymph
What are the major biological barriers to infection? - Answer: - genetic resistance
- normal microbiota
- phagocytosis
- inflammation
In what ways does the normal microbiota benefit the host? - Answer: - limiting nutrient
availability
pg. 3 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
, - preventing pathogen attachment to host cell surfaces
- synthesizing antimicrobial agents
- development of the immune system
- use of probiotics
What is the definition of phagocytosis? - Answer: to eat hallow vessel
What are the four steps of phagocytosis? - Answer: - chemotaxis
- attachment
- engulfment
- digestion
What are the three major types of cells in whole blood? - Answer: - erythrocytes
- leukocytes
- thrombocytes
What are the two major categories of leukocytes? - Answer: - granulocytes
- agranulocytes
How are the two categories of leukocytes further classifies according to their appearance in the
Wright stain? - Answer: - granulocytes: basophils, eosinophils, neutrophils
- agranulocytes: monocytes, lymphocytes
What is the fluid portion of blood called (a) before and (b) after the clotting factors are
removed? - Answer: (a): plasma
(b): serum
What is the inflammation response? - Answer: - damage to host tissues produces injured and
dead cells
- cells in damaged tissues release mediators
- tissue repair and regeneration occurs
- inflammation response is shut down
pg. 4 ELIWAN EXAMINERS – YOUR SHORTCUT TO EXAM SUCCESS.
