MDSC 515 CORRECT STUDY EXAM GUIDED
QUESTIONS AND ANSWERS SURE A+
✔✔exotoxin - ✔✔-bacteria will shoot it out or inject it into the cell
-proteins resemble enzymes
-secreted - into cells or extracellular matrix
-released
-can act at removed site
-denatured by heat/enzymes
-high biological activity
-specific actions
-cytotoxic activity
-antigenic (antitoxin)
✔✔endotoxin - ✔✔eg. lipopolysaccharide (LPS)
-part of cell wall
-released
-systemic effect - pro-inflammatory
-other gram-positive cell wall components such as peptidoglycan and lipoteichoic acid
have similar effects
✔✔endotoxins as pathogen associated molecular patterns (PAMPs) - ✔✔-pathogenic
molecules detected by the innate immune system
, -in bacteria they are components of cell wall
-influences the type of immune response to pathogen
-critical to the detection of pathogens (innate immunity)
-role in adaptive immunity - memory
-can also induce damaging inflammatory responses (septic shock)
✔✔Lipid A - ✔✔-main component of LPS that triggers an inflammatory response
-released from the cell in soluble form
-binds to soluble membrane-bound CD14 receptors
-triggers inflammatory response when CD14 interacts with Toll-like receptor 4
-leads to: production of cytokines (control the growth and activity of immune cells),
activation of complement (inflammatory response), activation of coagulation (blood to
solid or semi-solid state)
-inflammation, hemorrhage and septic shock (systemic inflammation and organ shut
down)
✔✔endotoxins and immune system - ✔✔-immune system uses endotoxins to detect
bacteria - can backfire causing a life-threatening response (septic shock)
✔✔gram stain - ✔✔-stain used to identify bacteria
-colour of bacteria when it is stained depends on the composition of the cell envelope
-gram-negative: LPS, thinner peptidoglycan layer - stain comes out
-gram-positive: no LPS, thicker peptidoglycan layer
✔✔types of exotoxins - ✔✔-pore-forming - pore in the membrane
-protein synthesis inhibitors
-second messenger pathway modifiers
-immune system inactivators
-proteases (cut up proteins)
✔✔pore-forming exotoxins - ✔✔-protein from bacteria forms a pore in the cell
membrane
-often results in cell lysis
✔✔AB toxins - ✔✔-protein synthesis inhibitors
-second messenger pathway modifiers
-B subunit receptor is carrying the A subunit (active domain)
-receptor-mediated
-A subunit has different activity depending on the pathogen
✔✔super antigens - ✔✔-immune system activators
-responsible for some severe manifestations of Group A streps and Staphylococcus
infections
✔✔flagella - ✔✔-help bacteria move or bind
QUESTIONS AND ANSWERS SURE A+
✔✔exotoxin - ✔✔-bacteria will shoot it out or inject it into the cell
-proteins resemble enzymes
-secreted - into cells or extracellular matrix
-released
-can act at removed site
-denatured by heat/enzymes
-high biological activity
-specific actions
-cytotoxic activity
-antigenic (antitoxin)
✔✔endotoxin - ✔✔eg. lipopolysaccharide (LPS)
-part of cell wall
-released
-systemic effect - pro-inflammatory
-other gram-positive cell wall components such as peptidoglycan and lipoteichoic acid
have similar effects
✔✔endotoxins as pathogen associated molecular patterns (PAMPs) - ✔✔-pathogenic
molecules detected by the innate immune system
, -in bacteria they are components of cell wall
-influences the type of immune response to pathogen
-critical to the detection of pathogens (innate immunity)
-role in adaptive immunity - memory
-can also induce damaging inflammatory responses (septic shock)
✔✔Lipid A - ✔✔-main component of LPS that triggers an inflammatory response
-released from the cell in soluble form
-binds to soluble membrane-bound CD14 receptors
-triggers inflammatory response when CD14 interacts with Toll-like receptor 4
-leads to: production of cytokines (control the growth and activity of immune cells),
activation of complement (inflammatory response), activation of coagulation (blood to
solid or semi-solid state)
-inflammation, hemorrhage and septic shock (systemic inflammation and organ shut
down)
✔✔endotoxins and immune system - ✔✔-immune system uses endotoxins to detect
bacteria - can backfire causing a life-threatening response (septic shock)
✔✔gram stain - ✔✔-stain used to identify bacteria
-colour of bacteria when it is stained depends on the composition of the cell envelope
-gram-negative: LPS, thinner peptidoglycan layer - stain comes out
-gram-positive: no LPS, thicker peptidoglycan layer
✔✔types of exotoxins - ✔✔-pore-forming - pore in the membrane
-protein synthesis inhibitors
-second messenger pathway modifiers
-immune system inactivators
-proteases (cut up proteins)
✔✔pore-forming exotoxins - ✔✔-protein from bacteria forms a pore in the cell
membrane
-often results in cell lysis
✔✔AB toxins - ✔✔-protein synthesis inhibitors
-second messenger pathway modifiers
-B subunit receptor is carrying the A subunit (active domain)
-receptor-mediated
-A subunit has different activity depending on the pathogen
✔✔super antigens - ✔✔-immune system activators
-responsible for some severe manifestations of Group A streps and Staphylococcus
infections
✔✔flagella - ✔✔-help bacteria move or bind
