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test2
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27
Microbiology
Undergraduate 2
04/08/2013

Additional Microbiology Flashcards

 


 

Cards

Term
Humoral Cell immunity
Definition
works to eliminate extracellular antigens in blood stream, B cells responsible for this immunity, once they are activated they differentiate into plasma cells that secrete antibodies
Term
Cell-mediated immunity
Definition
deals with antigens residing within a host cell, directed by t-cells
Term
Opsonization
Definition
Fc region of antibody can attach to its receptor on a phagocyte making antibody coated antigens easier to identify and engulf
Term
Antibody dependent cellular toxicity
Definition
when multiple IgG antibodies bind to infected cell, it becomes a target for natural killer cells, the NK cells bind to the Fc region of IgG and deliver compounds directly
Term
MHC I
Definition
present antigens made within the cell, produced by all nucleated cells, antigens recognized by cytotoxic t cells (respond to endogenous antigens)
Term
MHC II
Definition
present antigens taken up in a cell, only specialized antigen presenting cells make MHC II molecules, antigens recognized by t helper cells (respond to exogenous antigens)
Term
B cell activation
Definition
- when b cell receptor binds to t dependent antigen, b cell takes it in by endocytosis and encloses it within an endosome, antigen degraded and delivered to MHC II molecules on surface of b cell where they are presented to Th cells which scan naïve b cell to determine if it has encountered an antigen it can recognize, if Th’s antigen receptor binds to peptide fragments being presented, the t cell activates the b cell by delivering cytokines to b cell and initiating clonal expansion
Term
T independent antigens activation
Definition
- have multiple, repeating epitopes so clusters of b cell receptors bind to antigen simultaneously leading to b cell activation without Th cells
Term
T cell activation
Definition
dendritic cell detects pathogen, travels to secondary lymph organ and encounters naïve t cell, presents material, if t cell recognizes it, it becomes activated and starts clonal expansion
Term
Mechanisms of establishing infection
Definition
Adherence, colonization, delivering effector proteins to host cell (changing cell’s function/ structure), exploiting antigen sampling,
Term
how bacteria overcome Innate immunity
Definition
- can hide in host cell because innate system doesn’t recognize intracellular invaders, can bind to complement regulatory proteins to avoid complement system activation and postpone MAC formation, preventing encounters with phagocytes, avoiding recognition and attachment by phagocytes, surviving in phagocytes
Term
how bacteria overcome Adaptive immunity
Definition
- overcoming antibodies by producing IgA protease to break down IgA antibodies, antigenic variation so antibodies wouldn’t recognize them, mimicking host cell molecules (capsules, ect.)
Term
endotoxin
Definition
LPS, integral part of outer membrane, cnnot be converted to an effective toxoid for immunization, only in gram -, it is heat stable, produces an innate immune response (fever, drop in blod pressure) only systematic distribution is dangerous
Term
Exotoxins
Definition
proteins that may or may not be secreted by bacterial cells, found in gram + and – cells, can generally form toxoid and are inactivated by heat, generally potent toxins
Term
Virus like particle vaccine
Definition
empty capsids
Term
adjuvant
Definition
Enhances immune response to antigens, includes danger signals (patterns associated with tissue damage or invading microbes)
Term
Morbidity
Definition
incidence of a disease in a population at risk
Term
endemic
Definition
diseases constantly present in a population
Term
mechanical vector
Definition
indirect- carries microbe on its body from one place to another, flies on food, you eat food and get sick
Term
biological vector
Definition
direct- carrier either injects the human with pathogen or it bites human
Term
Intrinsic antibioticresistance
Definition
lack target entirely (cell wall, nucleotides), hidden target (underneath membrane), altered target (deformed)
Term
Selected antibiotic resistance
Definition
altered target (mutation by natural selection), repeat exposure of same antibiotic, incomplete treatment (typically happens with bacteriostatic agents)
Term
Acquired antibiotic resistance
Definition
- horizontal gene transfer, spontaneous mutation
Term
What are the acquired actions through horizontal gene transfer that contribute to resistance?
Definition
Enzymatic degradation- encodes enzymes to attack antibacterial cells, changes charge, pH, solubility and prevents it from entering cell
Uptake blockage
Extrusion- bacteria spit antibodies out
Term
Why are antibiotics not effective on viral infections?
Definition
Viruses don’t have cell walls or ribosomes and rely on host machinery for replication, therefore it is difficult to target viruses without damaging human cells
Term
3 targets that are used to treat fungal infections
Definition
Cell wall synthesis- chitin
Plasma membrane- ergosterol
Cell division- tubulin (spindle apparatus) not unique to fungus, has to build up in sytem
Term
What are thought to be the main mechanisms for current antiprotozoal and antihelminthic drugs?
Definition
Inhibit biosynthetic pathways or neuromuscular functions
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