Microbiology 3

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Microbiology 3
2010-04-13 22:57:11
Microbiology Test 3

Microbiology Chapters 13 - 16
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  1. What are the distinguishing characteristics of viruses? *
    • Contain either DNA or RNA not both
    • Need a host for replication
    • Virions must be assembled before moving to a new host
    • Acellular
  2. How do you describe virus structure? *
    nucleic acid and capsid proteins with the viral genome on the inside (single or double stranded DNA or RNA)

    • Isometric - Polyhedral (20 sided) spherical
    • Helical - Creates a protein tub with the nucleic acid on the inside
    • Complex - Isometric top filled with DNA/RNA, helical body, base plate, tail fibers the helical shape acts as a needle and head acts as a syringe (usually naked)
  3. What makes up a virus? *
    nucleic acid and capsid proteins with the viral genome on the inside (single or double stranded DNA or RNA)
  4. How are viruses classified?
    • By genome type (DNA or RNA, double or single stranded, single molecule or segmented)
    • By virion shape (isometric, helical, complex)
    • Presence or absence of envelope (naked or enveloped)
  5. What is meant by virus replication?
    Making more viruses/virions (whole virus particle)
  6. What is the steps in virus replication?
    • Attachment - virus attaches by the spikes on the outside and looks for receptors on outside of host
    • Entry - direct penetration, membrane fusion, endocytosis
    • Synthesis - new manufacturing of particles
    • Assembly & Release - everything for the virus is assembled and the cell either bursts or the virus pushes through the membrane to burst it
  7. How do we characterize (what are the types of) viral disease? What is an example of each
    • Acute - Measles - Onset of infection, get sick, then get better and disease is gone
    • Latent - Chicken Pox/Shingles - Onset of infection, get sick, then get better but disease hides and can be reactivated later
    • Chronic - Hepatitis B/C - Onset of infection, get sick, get better but virus never leaves and you always shed it
    • Slow - HIV/AIDS - Onset of infection, get sick, get better, slowly get sick again (as virus replicates in your t-cells) can take 10-20 years to get sick again
  8. What are prions? How are they involved in disease?
    Prions are infectious proteins folded into wrong shape and can bump into good cellular cells and turn them to fold wrong (mad cow disease).
  9. How does culturing of viruses differ from the bacterial cultures you make in lab?
    Can not do simple broth or plates as a virus has to replicate inside of a hose cell. A plaque with a bacterial lawn can be injected with a virus. Chicken eggs can also be injected with a virus as they are similar to humans and this is how a lot of vaccines are made.
  10. What are the two branches of immunity? How do they differ?
    • Innate - inherited, will always be on, non-specific
    • Adaptive/Acquired - specificity, inducibility (can turn on or off), clonality, unresponsiveness to self, memory
  11. What are the cellular components of the immune system? *
    Blood, erythrocytes, platelets, leukocytes (granulocytes - eosinophil, basophil, neutrophil / agranulocytes - lymphocytes, monocytes), dendritic cells, macrophages
  12. Generally speaking, what are the jobs of each type of cell? *
    • Platelets - involved in healing
    • Eosinophil - defense against parasitic worms and allergic reactions
    • Basophil - release of histamine, inflammation reactions
    • Neutrophil - phagocytosis
    • Lymphocytes - involved in adaptive immunity
    • Monocytes - circulates, differentiate in tissue to macrophages & dendritic cells.
    • Dendritic Cells - gather antigen & present to lymphocytes
    • Macrophages - phagocytosis, signaling centers for rest of immune system
  13. What are the components of the innate immune system?
    Skin, Saliva, Mucous Membrane, Normal Flora, Enzymes/Proteins
  14. What characterizes an innate response? *
    Quick and nonspecific
  15. What are the different types of responses are carried out by the innate immune system?
    Phagocytosis, Inflammation, Fever
  16. What are the systemic (body-wide) responses associates with innate immunity?
    • Inflammation
    • Fever - last response
  17. What are the signs of inflammation?
    • Calor - Heat
    • Rubor - Redness
    • Tumor - Swelling
    • Dolor - Pain
    • Loss of function (sometimes)
    • Dilation of blood vessels
    • Increased "leakiness" of blood vessels
  18. What are the two branches of the adaptive immune response?
    Humoral & Cellular
  19. What are the components of the adaptive immune response? *
    • T-Cells:
    • Cytotoxic T-Cells go after affected cells or ones that have changed their protein is CD-8
    • Helper T-Cells target extracellular cells and their protein is CD-4

    • B-Cells:
    • Produce antibodies and have BCR's on their surface
  20. Which cells are involved in the adaptive response?
    T-Cells & B-Cells
  21. Where in the body do they mature? (T-Cells, B-Cells)
    • T-Cells - matures to a point in the bone marrow then goes to the thymus to finish maturing
    • B-Cells - matures totally in the bone marrow
  22. What are their jobs? (T-Cells, B-Cells)
    • T-Cells - recognize antigens presented by MHC molecules to recognize from a person or foreigner
    • B-Cells - Turn into plasma cells & make antibodies
  23. What characterizes each type of cell (how can we tell which is which)? *
    They each have certain receptors. Helper T-Cells have CD4, Cytotoxic T-Cells have CD8 and B-Cells have BCRs on their surface and make antibodies
  24. What are antibodies?
    Protein that binds to antigen
  25. What do they do? (antibodies)
    To identify and neutralize foreign objects
  26. What characterizes the antigen-antibody interaction?
    Its specific
  27. What are the outcomes of antibody-antigen interactions?
    • Neutralization - cover all receptors on a cell with antigens so virus/bacteria can not attach
    • Opsonization (direct) - an antibody to attach to a bacterium & to get ready to eat
    • Agglutination - a bunch of antibodies attach to different cells to help kill them off
    • Antibody-dependent cellular cytotoxicity (ADCC) - a lymphocyte attaches to one of our cells that is different and natural killers are sent out
  28. What occurs during a cellular response?
    Both Cytotoxic T-Cells and Helper T-Cells go after an affected cell
  29. How do B-Cells and T-Cells work together to form a humoral response?
    Antigen presenting cells talks to T-Cells which activates a B-Cell. Somewhere else a B-Cell (or the same B-Cell) recognizes the bacteria. Both the T-Cell and B-Cell is activated.
  30. What is meant by immune memory? Why is it significant?
    Once a foreigner is seen the B-Cells can recognize it again and immediately start making antibodies without having to go through the process of being presented the antigen by the T-Cells
  31. What types of relationships describe host-pathogen interactions?
    • Mutualism - both partners benefit (normal flora)
    • Parasitism - one benefits at the expense of the other (worms living off our tissue)
    • Commensalism - neither partner is benefiting/harmed or 1 may be benefiting but the other is not being effected
  32. What is meant by the term normal flora?
    Organisms that can normally be found on surfaces of/in the body and usually do not cause us harm and can actually help us.
  33. Where do they come from (how do we acquire them)?
    You get normal flora from your mother (when being born) and breathing
  34. Where in the body are they (normal flora) found?
    They are found everywhere in the body. Skin, gut, upper respiratory tract, upper and lower digestive tract, female/male urinary and reproductive systems, and eyes.
  35. What are the various types of reservoirs?
    Humans, other animals, non-living reservoirs (water supplies, dust particles, food supply)
  36. What are the portals of entry through which pathogens invade?
    Any openings on the body (ears, eyes, nose, insect bite etc...) and placenta
  37. What is pathogenicity?
    Ability of a pathogen to produce and infectious disease
  38. How do we define the term (pathogenicity)?
    Ability to inflict damage on a host
  39. What is implied in discussions of pathogenicity and virulence?
    Virulence factors contribute to the pathogenicity of an organism
  40. What type of pathogens are there?
    • Primary Pathogen - will cause disease in healthy individuals
    • Opportunistic Pathogen - will cause disease in only immunocompromised individuals
  41. What are Koch's postulates?
    • 1) Organism must be present in every case of the disease
    • 2) Organism must be grown in pure culture from the diseased host
    • 3) The same disease must be produces when the organism is introduced into a susceptible hose
    • 4) The organism must be recovered from an experimentally infected host
  42. How do they help us understand infectious disease?
    We can figure out what the actual organism is (by isolating it in different hosts), how long it takes to grow or cause illness, how it can be transfered
  43. What are some exceptions to the postulates?
    • Some organisms are human disease only and can not be given to another host (like HIV/AIDS)
    • Can not isolate the organism (grow it in a lab)
    • Some diseases are a combination of pathogens, environmental, or genetic factors
  44. How do we describe the course (stages) of a given disease? What happens in each stage?
    • Incubation Period - time between exposure & initial signs/symptoms
    • Prodromal - vague, general symptoms (start feeling bad but don't know why)
    • Illness - most severe signs & symptoms (where you'll go to the dr)
    • Decline - declining signs & symptoms (getting better)
    • Convalescence - no signs & symptoms (better)
  45. What are virulence factors?
    How much damage is caused. Invasion, Adhesion, Evasion
  46. What do they allow potential pathogens to do?
    virulence factors contribute to the pathogenicity (how much damage it can cause) of an organism

    Allow for invasion, adhesion, evasion, cause damage
  47. What are the types of virulence factors we discussed in class? *
    Toxins, Evasion (structures & strategies), and Extracellular Enzymes
  48. What are the portals of exit from the host? *
    The same as the entry (any opening of the body)
  49. What are the modes of transmission we discussed? *
    • Contact - (direct, indirect, and droplet)
    • Vehicle - (environment, inanimate objects)
    • Vector - A disease passed through another animal (mechanical - fly/roach and biological - mosquito)
  50. What are the terms used in epidemiology to describe when and where disease occurs? *
    • Incidence - number of new cases in a given area over a period of time
    • Prevalence - total number of cases in a given year over a period of time
    • Endemic - disease thats always present in an area
    • Sporadic - Disease popping up randomly
    • Epidemic - Sudden increase of a disease in an area
    • Pandemic - Multiple epidemics
  51. What are nosocomial infections? *
    associates with hospital
  52. What are the different types of nosocomial infections that can arise? *
    • Endogenous - The infectious agent came from the patient itself
    • Exogenous - The infectious agent came from the outside
    • Iatrogenic - Procedure, devices, or material induced
  53. What is the significance of nosocomial infections? *