Final Flashcards
(25 cards)
what is a lichen?
a mutualistic association with a fungus and cyanobacteria or alga
How does the lichen and fungus both benefit from their relationship?
the fungus is fed by the organic matter produced by the lichen. The lichen is protected by the fungus by the prevention of dehydration, promoting the dissolution and chelation of inorganic nutrients from the rock or other surfaces. The fungus facilitates the uptake of water.
What are the vertices and their representation on the triad triangle?
Pathogen (the what causing the disease), Host( the who, who the pathogen is affecting), Environment (where the pathogen is affecting the host)
What is the central component of the disease triad?
Time. Most infectious diseases have an incubation period, time between when the host is infected and when disease symptoms occur.
What are the characteristics of the host?
age, prior exposure, susceptibility, immune response
What are the characteristics of the pathogen?
toxicity, virulence, infectivity, susceptibility to antibiotics, and ability to survive outside the body
What are the characteristics of the environment?
climate, physical structures, population density, social structure
What are the stages of the host defenses?
Exposure, adherence, invasion, growth and colonization
What are human defense mechanisms?
adaptive and innate immunity, sterilization, autoclaves, antibiotics, vaccines. detergents, and native flora
What are bacterial virulence mechanisms?
adherence, invasion, degradative enzymes, exotoxins, endotoxins, superantigens, resistance, induction of excess inflammation
what are some diseases caused by streptococcus pyogenes?
strep throat, impetigo, SSTS, necrotizing fasciitis, and scarlet fever
What allows S. pyogenes to cause multiple diseases?
S. pyogenes has phages that encode for various virulence factors including SpeA,B,D,F. Can undergo lysosgenic conversion
What causes the common cold?
rhinovirus and coronaviruses, both SS RNA viruses
What causes the flu?
SS negative sense RNA, orthomyxovirus
What are the differences between the flu and col symptoms?
The cold has nasal discharge, sore throat, and slight malaise. The flu has fever, headache, malaise and vomiting and diarrhea(children)
Which two proteins describe the influenza virus?
Hemagglutinin and Neuraminidase
What is antigenic variation?
flu virus continually changing antigenicity of HA and NA to escape antibody mediated immune response
Which two factors contribute to antigenic variation?
antigenic shift and antigenic drift
Describe antigenic drift.
Occurs in A,B, and C. A missense mutation changes the amino acid sequence on a surface protein receptor. As a result, an antibody is not able to bind to the protein. Even though the structure has changes, the function of the protein is preserved.
Describe antigenic shift.
Occurs only in A. When a pig receives viruses from a bird and human there is rearrangement of chromosomes. This rearrangement introduces new strains.
What is hepatitis?
an acute disease in the live. Symptoms include jaundice, icetrus, cirrhosis, and ascites, and carcinogenic.
What are the types of hepatitis and their causes.
A: food, B: sexual, C&D: parentenal, and E: water
How does HepC evade the immune system?
cleaves TLR3 therefore TRIF cannot induce an immune response (inflammation)
How does HepB evade the immune system?
insufficient presentation of viral antigens to killer T cells and inhibition of IFN.
