Exam (elaborations)
MCPHS Microbiology Exam II :-Questions & Solutions
- Course
- Institution
MCPHS Microbiology Exam II :-Questions & Solutions
[Show more]
Content preview
MCPHS Microbiology Exam II :-Questions & SolutionsPathogenicity Right Ans - The ability to cause disease
Virulence Right Ans - the extent of pathogenicity
Portals of entry Right Ans - mucous membranes, skin, parenteral route
ID50 (infectious dose) Right Ans - The number of microbes that must enter
the body to establish infection in 50% of test animals is expressed as the ID50
LD50 Right Ans - lethal dose (of a toxin) for 50% of the test population
Adherence Right Ans - Adhesions / ligands bind to receptors on host cells,
form biofims
Glycocalyx: streptococcus mutans
Fimbriae: E.coli
M proteins: Strepoccus pyogenes
Pili, flagella, glycoproteins, lipoproteins
Capsules - resist phagocytosis Right Ans - Strep. Pneumoniae, Hib, bacillus
anthracis
cell wall components Right Ans - M proteins: mediates attachment and
resists phagocytosis (strep. pyogenes)
Opa protein: assist attachment and recept mediated endocytosis, inhibs helper
t cells (n. gonorrhoeae)
Mycolic acid: Waxy, resists digestion (mycobacterium TB)
Enzymes Right Ans - Coagulase: coagulates fibrinogen
Kinases: digest fibrin clots
hyaluronidase: hydrolyzes hyaluronic acid
Collagenase: hydrolyzes collagen
IgA proteases: destroys IgA antibodies
antigenic variation Right Ans - Alteration of surface antigens to avoid
detection by host antibodies
Examples: flu, gonorrhea, trypanosoma brucei gambiense
,Invasins: Penetration into the host cell cytoskeleton Right Ans - Salmonella
alters host actin to enter a host cell
Listeria uses actin to move from one cell to the next
Direct damage caused by Right Ans - disrupting the host cells function
produces waste products
toxins
induce hypersensitive reactions
damage immediate vicinity
use hosts nutrients (iron) -siderophores
Siderophores Right Ans - proteins that free host stores of iron
Toxin Right Ans - substance that contributes to pathogenicity
Toxoid Right Ans - inactivated toxin used in a vaccine
Antitoxin Right Ans - antibodies against a specific toxin
Endotoxins Right Ans - the lipid portions of lipopolysaccharides (LPS) that
are part of the outer membrane of the cell wall of gram-negative bacteria. The
endotoxins are liberated when the bacteria die and the cell wall breaks apart.
PART OF BACTERIAL CELL NOT A PRODUCT
Lipid NOT proteins
all produce same SS
Exotoxins Right Ans - specific for a structure or function in host cell
Can be gram pos or neg
Are proteins, enzymes
secreted into medium during log phase
most lethal
produce SS
Classification of exotoxins Right Ans - 1. Based on host cell attacked
(cardiotoxin)
2. Disease they are associated with: tetanus
, 3. Bacterium that produces it: botulinum
4. Structure/function: A-B, Membrane-disrupting, superantigens
A-B exotoxin Right Ans - A: Alters cell function by inhibiting protein
synthesis
B: Binding compenent
examples: Corynebacterium diphtheria, clostridium botulinum, c. tetani,
vibrio cholerae
membrane disrupting exotoxins Right Ans - lyse host cells by disrupting
plasma membranes/disrupt phospholipid bilayer
Leukocidins: kill phagocytic leukocytes
Hemolysins: destroy RBCs
-Streptolysins
example: strep. pyogenes
Superantigens Right Ans - cause an intense immune response due to
release of cytokines from host cells
Symptoms: fever, nausea, vomiting, diarrhea, shock, death
Example: Staph. aureus
Combine with macrophages
Stimulate T cells
LAL Assay - limulus amebocyte lysate assay Right Ans - detects endotoxins
(horseshoe crabs white blood cells) will produce a clot
Commensalism Right Ans - one organism benefits and the other is
unaffected
Etiology Right Ans - study of the cause of disease
Pathogenesis Right Ans - development of disease
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LeCrae. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $18.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67163 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now