Microbiology Exam #4

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  1. Innate Vs. Adaptive Immunity
    Innate = Defenses against any pathogen; present at birth; good against pathogen; no memory

    Adaptive = Defenses against or resistance to a specific pathogen; specific reaction to a pathogen; acquired through exposure; memory response
  2. Toll-Like Receptors
    Receptors on macrophages that recognize pathogens by looking for PAMPs (Pathogen Associated Molecular Patterns - peptidoglycan, endotoxin, flagella protein, double stranded RNA)
  3. Components of 1st Line of Defense
    Physical = skin (sebum), epidermis (consists of tightly packed cells with Keratin), mucous membranes (mucous traps microbes), ciliary escalator (microbes trapped in mucous are transported from lungs), lacrimal apparatus (washes eye), saliva (washes off microbe), urine (flows out), vaginal secretions (flows out)

    Chemical = fungistatic fatty acid in sebum, low pH of skin, lysozyme in perspiration, tears, saliva, & urine, low pH of gastric juice, low pH of vaginal secretions
  4. 2nd Line of Defense
    Blood consists of plasma & formed elements (RBCs, WBCs, T cells, B cells, & Platelets)
  5. WBCs
    2 Types:

    • 1.  Granulocytes
    • Neutrophils - phagocytosis
    • Basophils - histamine, allergies, inflammation
    • Eosinophils - kills parasites, allergies

    • 2.  Agranulocytes
    • Monocytes (Macrophages) - phagocytosis
    • Dendritic Cells - phagocytosis, present antigen to adaptive immune cells, bridge to 3rd line of defense
    • Natural Killer Cells - destroy target cells, kill abnormal cells
  6. Phagocytosis
    Chemotaxis = Chemotactic chemicals produced (chemokines) along a gradient causing movement of phagocytes to microbes - movement toward a chemical signal

    Adherence = Attachment of phagocyte's membrane to microbe; opsonization (coating of microbe by antibodies or complement); toll-like receptors cause activation of phagocyte to release cytokines

    Ingestion = Pseudopods engulf microbes & fuse together forming phagosome; pH is lowered inside the phagosome

    Digestion = Phagosome fuses with lysozome creating the phagolysozome; lysozome degrades peptidoglycan while other enzymes break down other cell components; after microbe is digested, vesicle becomes a residual body & expels waste outside the cell; also presents antigens to the 3rd line of defense
  7. Ways Microbes Evade Phagocytosis
    • Inhibit Adherence =  M protein, capsules
    • Kill Phagocytes; = Leukocidins
    • Lyse Phagocytes =  Membrane attack complex
    • Escape Phagosome
    • Prevent Phagosome-Lysozome Fusion
    • Survive in Phagolysozome
  8. Inflammation
    Body's response to cell damage characterized by redness, heat, pain, swelling

    Vasodilation = increased permeability of blood vessels; release of acute phase proteins (histamines, kinins, prostaglandins, leukotrienes) causes increased leakiness of vessels to allow migration of leukocytes to site of damage; blood clots can form around abcess to prevent dissemination of infection

    Phagocyte Migration & Phagocytosis = phagocytes normally flow with blood through vessels; can adhere loosely & then bind tightly when stimulated; then follow chemokine gradient & can squeeze through endothelial cells to move into tissues; adhere to microbes & phagocytose them

    Tissue Repair = final stage; new cells are produced by the supporting tissues and/or the functioning tissue; can be abnormal if fibroblasts are activated to produce scar tissue
  9. Complement
    Complement System = defensive system consisting of over 30 proteins produced by the liver and found circulating in blood serum and within tissues throughout the body

    Complements the cells of the immune system in destroying microbes; not adaptable and does not change over the course of a person's lifetime (belongs to the innate immune system)
  10. What Complement Activation Leads To
    • Inactive C3 splits into activated C3a and C3b.
    • C3b binds to the surface of a microbe, and receptors on phagocytes attach to the C3b.  Thus C3b enhances phagocytosis by coating a microbe, opsonization promotes attachment of a phagocyte to a microbe.
    • C3b also initiates a series of reactions that result in cytolysis.
    • The transmembrane channels of the MAC result in cytolysis.
    • C3a and C5a bind to mast cells and cause them to release histamine and other chemicals that increase blood vessel permeability during inflammation.  C5a also functions as a very powerful chemotactic factor that attracts phagocytes to the site of an infection.
  11. Complement Pathways
    • Classical = Initiated when antibodies bind to antigens
    • Alternative = Does not involve antibodies; activated by contact between certain complement proteins and a pathogen
    • Lectin = When macrophages ingest bacteria, viruses, and other foreign matter by phagocytosis, they release cytokins that stimulate the liver to produce lectins, proteins that bind to carbs
  12. Interferon
    Class of similar antiviral proteins produced by certain animal cells, such as lymphocytes and macrophages, after viral stimulation; interferes with viral multiplication
  13. Types of Interferon
    Alpha & Beta Interferon = produced by virus-infected host; induces uninfected cells to produce antiviral proteins that prevent viral replication

    Gamma Interferon = produced by lymphocytes; induces neutrophils and macrophages to kill bacteria; causes macrophages to produce nitric oxide that appears to kill bacteria as well as tumor cells by inhibiting ATP production
  14. Antimicrobial Peptides
    Inhibit cell wall synthesis; form pores in plasma membranes, resulting in lysis; destroy DNA and RNA

    Produced by nearly all plants and animals, and bacterial resistance to AMPs has not yet been seen
  15. B Cells & T Cells
    B Cells = type of WBC; differentiates into andtibody-secreting plasma cells and memory cells; recognize antigens and make specific antibodies against them

    T Cells = type of WBC; develops from a stem cell processed in the thymus gland that is responsible for cell-mediated immunity; contact with an antigen complementary to a TCR can cause certain types of T cells to proliferate and secrete cytokines rather than antibodies
  16. Antibodies
    Globulin proteins aka immunoglobulins (Ig); made in response to an antigen

    Structure = antibody monomer has 4 protein chains joined by disulfide links and other bonds to form a Y-shaped molecule; the two sections located at the ends of the y's arms are called variable regions
  17. Classes of Antibodies
    IgG = enhances phagocytosis; neutralizes toxins and viruses; protects fetus and newborn

    IgM = especially effective against microorganisms and agglutinating antigens; first antibodies produced in response to initial infection

    IgA = localized protection of mucosal surfaces

    IgD = serum function not known; presence on B cells functions in initiation of immune response

    IgE = allergic reactions; possibly lysis of parasitic worms
  18. MHC (Major Histocompatibility Complex) Molecules
    • Collection of genes that encode molecules of genetically diverse glycoproteins that are found on the plasma membranes of mammalian nucleated cells
    • Identifies the host and its use here prevents the immune system from making antibodies that would be harmful to the host
  19. 5 Processes That Occur Following Binding of Antibody to Antigen
    Agglutination = antibodies cause antigens to clump together

    Opsonization = the antigen, such as a bacterium, is coated with antibodies that enhance its ingestion and lysis by phagocytic cells

    Neutralization = IgG antibodies inactivate microbes by blocking their attachment to host cells and neutralize toxins in a similar manner

    Activation of Complement System = triggered by either IgG or IgM antibodies which llyses the microbe, which then attracts phagocytes and other defensive immune system cells to the area

    Antibody-Dependent Cell-Mediated Cytotoxicity = resembles opsonization in that the target organism becomes coated with antibodies; however, destruction of the target cell is by immune system cells that remain external to the target
  20. Classes of T Cells
    Helper T Cell = coordinates and regulates the immune response by secreting interleukins; regulate other t cells, b cells, leukocytes (macrophages and granulocytes); can recognize an antigen presented on the surface of a macrophage

    Cytotoxic T Cell = destroys infected cells as well as pathogens by releasing destructive compounds that will kill the pathogen; secretes toxins and digestive enzymes as well

    Supressor T Cell = inhibit and regulate the immune response

    Natural Killer Cell = can attack cancer and some pathogens
  21. Types of Professional Antigen-Presenting Cells
    Dendritic Cells = present all types of antigens, but present viral antigens efficiently

    Macrophages = present bacterial antigens well 

    B Cells = present peptides of soluble protein antigens, such as protein toxins, that they have internalized via their antigen receptors
  22. NK Cells
    • Not immunologically specific; they do not need to be stimulated by an antigen
    • They first contact the target cell and determine whether it expresses MHC class I self-antigens; if it does not they kill the target cell
  23. Cytokines
    A small protein released from human cells that regulates the immune response; directly or indirectly may induce fever, pain, or T cell proliferation
  24. Immunological Memory
    • The capacity of the body's immune system to remember an encounter with an antigen due to the production of circulating antibodies and expanded clones of long-lived B and T cells during the primary response
    • Ensures that subsequent infections with the same pathogen will provoke a faster, stronger, longer secondary immune response
  25. 4 Types of Acquired Immunity
    Naturally Acquired Active Immunity = develops when a person is exposed to antigens, becomes ill, and then recovers.  One acquired, immunity is lifelong for some diseases

    Naturally Acquired Passive Immunity = involves the natural transfer of antibodies from mother to her infant.  Antibodies in a pregnant woman cross the placenta to her fetus

    Artificially Acquired Active Immunity = result of vaccination; introduces vaccines into the body

    Artificially Acquired Passive Immunity = involves the injection of antibodies (rather than antigens) into the body.  These antibodies come from an animal or person who is already immune to the disease
  26. Vaccines
    A suspension of organism or fractions of organisms that is used to induce immunity

    Live Attenuated Vaccines = includes a live virus that has mutated so that it has reduced ability to grow in human cells and is no longer pathogenic to humans

    Inactivated Killed Vaccines = Includes virus particles that have been treated with formalin, heat, or irradation so that they are no longer able to replicate

    Subunit Vaccines = use only those antigenic fragments of a microorganism that best stimulate an immune response

    Conjugated Vaccines = involves attachment of a polysaccharide to a protein

    Nucleic Acid (DNA) Vaccines = plasmids of "naked" DNA injected into muscle results in the production of the protein antigen encoded in the DNA; the protein antigens are carried to the red bone marrow and stimulate both humoral and cellular immunity
  27. Monoclonal Antibodies
    Antibodies that recognize a single, specific epitope of an antigen of interest

    When a hybridoma is grown in culture, its genetically identical cells continue to produce the type of antibody characteristic of the ancestral B cell

    Useful because they are uniform, highly specific, and they can be produced readily in large amounts
  28. Precipitation & Agglutination Reactions
    Precipitation Reactions = involve the reaction of soluble antigens with IgG or IgM andtibodies to form large, interlocking molecular aggregates called lattices; used in precipitin ring test and immunodiffusion tests

    Agglutination Reactions = involve either eithe particulate andtigens or soluble antigens adhering to particles; these antigens can be linked together by antibodies to form visible aggregates; used in direct agglutination tests and indirect agglutination tests
  29. Neutralization Reactions
    Antigen-antibody reaction in which the harmful effects of a bacterial exotoxin or a virus are blocked by specific antibodies
  30. Complement-Fixation Reactions
    Antibodies that do not produce a visible reaction, such as precipitation or agglutination, can be demonstrated by the fixing of complement during the antigen-antibody reaction
  31. Indirect Vs. Direct ELISAs
    Indirect = detects antibodies in a patient's sample rather than an antigen such as a drug; antigen is adsorbed to well, patient serum is added and complementary antibody binds to antigen, enzyme-linked anti-HISG is added and binds to bound antibody, enzyme's substrate is added and reaction produces a product that causes a visible color change

    Direct = tests to detect the presence of drugs in urine; antibody is adsorbed to well, patient sample is added and complementary antigen binds to antibody, enzyme-linked antibody specific for test antigen is added and binds to antigen, forming sandwich, enzyme's substrate is added, and reaction produces a product that causes a visible color change
  32. Hypersensitivity
    Refers to an antigenic response beyond that which is considered normal; aka allergy

    Hypersensitivity responses occur in individuals who have been sensitized by previous exposure to an antigen; aka allergen

    Type 1 (Anaphylactic) = IgE binds to mast cells or basophils; causes degranulation of mast cell or basophil and release of reactive substances such as histamine - anaphylactic shock from drug injections and insect venom; common allergic conditions such as hay fever or asthma

    Type 2 (Cytotoxic) = antigen causes formation of IgM and IgG antibodies that bind to target cell; when combined with action of complement, destroys target cell - transfusions reactions, Rh incompatibility

    Type 3 (Immune Complex) = antibodies and antigens form complexes that cause damaging inflammation - arthus reactions, serum sickness

    Type 4 (Delayed Cell-Mediated, or Delayed Hypersensitivity) = antigens activate Tc that kill target cell
  33. HLA Typing
    • Used to identify and compare HLAs (human leukocyte antigen)
    • Certain HLAs are related to an increased susceptibility to specific diseases
    • Medical application of HLA typing is to identify such susceptibility and in transplant surgery
  34. Autoimmunity
    Condition in which one's own immune system cannot discriminate between foreign and self antigens
  35. Transplant Rejection
    Specific immunological eradication of a graft

    Hyperacute Rejection = preexisting antibodies in recipient, Ag-Ab complex, mismatched blood groups

    Acute Rejection = due to difference in MHC I and II alleles, happens in 10 - 14 days and is cell-mediated,

    Chronic Rejection = due to difference in minor histocompatibility antigens, slow progressive (months to years), both humoral and cellular immunity

    Graft Vs Host Rejection = lymphocytes in a graft attacking the recipient, if immunocompromised
  36. Types of Transplants
    • Privileged Sites and Privileged Tissue
    • Stem Cells
    • Grafts
    • Bone Marrow Transplants
  37. How Cancer Cells Escape Detection By The Immune System
    • Some cancer cells can produce proteins that shut down the immune system in the area around the tumor
    • Some cancers occur in places that the immune system has a hard time getting to such as the brain
  38. Immunodeficiencies (Congenital Vs. Acquired)
    Congenital = the inability, due to an individual's genotype, to produce specific antibodies or T cells

    Acquired = the inability, obtained during the life of an individual, to produce specific antibodies or T cells, due to drugs or disease
  39. HIV Infection
    • Retrovirus that has two identical strands of RNA, the enzyme reverse transcriptase, and an envelope of phospholipid
    • Spread by dendritic cells that cary it to the lymphoid organs where it contacts cells of the immune system; viral DNA becomes integrated into the chromosomal DNA of the host cell
  40. Cell Types Infected by HIV & How This Affects The Immune System
    T Cells

    Causes the immune system to shut down
  41. Sties, Pimples, Carbuncles, Folliculitis
    • Causative Agent = S. aureus
    • Identifying Characteristic = Localized infection, with or without pus
  42. Impetigo
    • Causative Agent = S. aureus
    • Identifying Characteristic = Highly contagious, vesicular rash; passed through direct contact
  43. Toxemia - Scalded Skin Syndrome
    • Causative Agent = S. aureus
    • Identifying Characteristic = Staph toxins enter blood stream; results in fever, rash, and shock
  44. Erysipelas
    • Causative Agent = S. pyogenes
    • Identifying Characteristic = Reddish patches on skin or mucous membranes with fever
  45. Necrotizing Fasciitis
    • Causative Agent = S.pyogenes; MRSA
    • Identifying Characteristic = Bacteria invade tissue and destroy it
  46. Otitis Externa
    • Causative Agent = Pseudomonas aeruginosa
    • Identifying Characteristic = Ear infection - swimmers ear
  47. Burn Infection/Dermatitis
    • Causative Agent = P. aeruginosa
    • Identifying Characteristic = Opportunistic
  48. Acne
    • Causative Agent = Propionibacterium
    • Identifying Characteristic = Most common skin disease; G- rods; metabolize sebum in hair follicles
  49. Warts
    • Causative Agent = HPV
    • Identifying Characteristic = Skin cells proliferate and cause benign growths; spread by direct contact
  50. Smallpox
    • Causative Agent = Variola virus
    • Identifying Characteristic = Enters respiratory tract and causes pustular rash; passed by aerosols, no tx
  51. Chickenpox
    • Causative Agent = Varicella virus
    • Identifying Characteristic = Vesicular rash; latent in nervous system
  52. Shingles
    • Causative Agent = Varicella virus
    • Identifying Characteristic = Vesicular rash; latent in nervous system - reactivates across single dermatome
  53. Herpes Simplex (Cold Sore)
    • Causative Agent = HSV-1
    • Identifying Characteristic = Vesicles around mouth (also in GI Tract); 90% infected; can cause encephalitis
  54. Measles (Rubeola)
    • Causative Agent = Measles virus
    • Identifying Characteristic = Macular rash; Koplik's spots in mouth diagnostic indicator; MMR vaccine
  55. German Measles (Rubella)
    • Causative Agent = Rubella virus
    • Identifying Characteristic = German measles; transmitted respiratory route; milder rash; major concern during pregnancy
  56. Fifth Disease and Roseola
    • Causative Agent = Human Parvovirus B19 HHV-6,7
    • Identifying Characteristic = Mild macular rash on face (slapped face); high fever; rash on body
  57. Mycoses
    • Causative Agent = Trichophyton (hair, skin, nails); Microsporum (hair, skin); Epidermophyton (skin, nails)
    • Identifying Characteristic = Tinea capitis (head); Tinea pedis ringworm, athletes foot, jock itch, etc; metabolize keratin
  58. Candidiasis
    • Causative Agent = Candida albicans
    • Identifying Characteristic = Yeast infection; thrush; commonly found in immunosuppressed
  59. Scabies
    • Causative Agent = Mites Sarcoptes scabiei
    • Identifying Characteristic = Burrow under skin; papules and itching
  60. Pediculosis
    • Causative Agent = Pediculus humanis (lice)
    • Identifying Characteristic = Itchiness due to sensitization to louse saliva
  61. Conjunctivitis
    • Causative Agent = Hemophilus influenzae (bacteria); can be viral too
    • Identifying Characteristic = Inflammation of the conjunctiva of the eye; aka pink eye
  62. Trachomatis
    • Causative Agent = Chlamydia trachomatis
    • Identifying Characteristic = G- coccoid; swelling and pus; birth canal or wrimming; Trachoma - scar
  63. Opthalmia Neonatorum
    • Causative Agent = Neisseria gonorrhoeae
    • Identifying Characteristic = Acquired during birth; acute infection with pus; blindness; newborns tx with antibiotics
  64. Herpetic Keratitis
    • Causative Agent = HSV-1
    • Identifying Characteristic = Inflammation of cornea
  65. Ameobic Keratitis
    • Causative Agent = Acanthamoeba
    • Identifying Characteristic = Fresh water, usually in contact lens wearers who make own saline
  66. Urethritis
    • Causative Agent = Opportunistic G- bacteria
    • Identifying Characteristic = Inflammation of the urethra
  67. Cystitis
    • Causative Agent = E. coli, Staphylococcus saprophyticus
    • Identifying Characteristic = Inflammation of the bladder
  68. Ureteritis
    • Causative Agent = Opportunistic G- bacteria
    • Identifying Characteristic = Inflammation of the ureters
  69. Pyelonephritis
    • Causative Agent = E. coli
    • Identifying Characteristic = Inflammation of the kidneys
  70. Leptospirosis
    • Causative Agent = Leptospira interrogans
    • Identifying Characteristic = Transmitted by urine contaminated water from animals (dogs, rats); causes fever, chills, and can lead to liver and kidney issues
  71. Gonorrhea
    • Causative Agent = Neisseria gonorrhoeae
    • Identifying Characteristic = Attaches to mucosal cells using fimbriae; results in painful urination and pus discharge in men; can cause blindness if passed to infant during birth
  72. Nongonococcal Urethritis (NGU)
    • Causative Agent = Chlamydia trachomatis
    • Identifying Characteristic = Inflammation of urethra; chlamydia most common STI; mild symptoms; also causes blindness in infants
  73. Pelvic Inflammatory Disease
    • Causative Agent = N. gonorrhoeae; C. trachomatis
    • Identifying Characteristic = Bacterial infection of the female pelvic organs; can result in blockage of uterine tubes and sterility
  74. Syphillis
    • Causative Agent = Treponema pallidum
    • Identifying Characteristic = Spirochete; not grown in media; has 4 distinct stages =  primary - sore at site of infection, secondary - rash on skin and mucous membranes, latency - can last years, tertiary - presence of gummas (skin lesions); also affect cardiovascular and nervous systems
  75. Lymphogranuloma Venereum
    • Causative Agent = C. trachomatis
    • Identifying Characteristic = Disease of tropics; initial lesion and then blockage of lymphatic system leading to swollen genitals
  76. Bacterial Vaginosis
    • Causative Agent = Gardenella vaginalis
    • Identifying Characteristic = Infection of the vagina (no inflammation); diagnosis based on increased pH; fishy odor and presence of clue cells (vaginal epithelial cells coated with bacteria)
  77. Genital Herpes
    • Causative Agent = Herpes Simplex Virus type II (also HSV-1)
    • Identifying Characteristic = Fluid filled vesicles on genitals; virus goes latent in nerve cells; virus can cause recurrent lesions upon reactivation
  78. Genital Warts
    • Causative Agent = HPV
    • Identifying Characteristic = 1/4 of women infected; linked with cervical cancer; causes wart like growths on genitals in females; asymptomatic in males
  79. Candidiasis (Yeast Infection)
    • Causative Agent = Candida albicans
    • Identifying Characteristic = Lesions in vagina with itching and irritation; treated with OTC medications
  80. Trichomoniasis
    • Causative Agent = Trichomonas vaginalis
    • Identifying Characteristic = Protozoan infection of vagina; raises pH
  81. Toll-like receptors are proteins that bind to what?
    Pathogen-associated molecular patterns
  82. The lacrimal apparatus is considered what type of factor in the 1st line of defense?
  83. What component is found in tears, saliva, and perspiration that is harmful to bacteria?
  84. The primary phagocyte in the blood is which cell?
  85. Monocytes mature into what cells?
  86. The coating of microbes with serum proteins is known as
  87. Bacteria can prevent the formation of what to escape phagocytosis?
  88. Inflammation results in blood vessel permeability and diapedesis of immune cells
  89. Activation of C3 results in which of the following?
    Opsonization and cell lysis
  90. Which interferon is important in activation of immune cells and antigen presentation?
  91. Lymphocytes that mature in the bone marrow are called
    B cells
  92. Lymphocytes that mature in the thymus are called
    T cells
  93. B and T cells that react strongly to self antigen are eliminated during the selection process
  94. The part of the antibody molecule that binds to antigen is part of the variable region
  95. IgM is a class of antibodies that can form pentamers
  96. The T cell receptor recognizes free antigen that is present in the serum and tissues
  97. CD4+ T cells recognize antigen presented using __ on which cells?
    MHC II---antigen presenting cells
  98. Cytotoxic T cells lyse target cells or induce apoptosis using the molecules
    Perforin and Granzyme
  99. The secondary response is due to the presence of memory cells and occurs at a faster rate than the primary response
  100. The immunity developed after infection is called naturally acquired active immunity
  101. Name the 5 mechanisms for pathogen destruction/inactivation that results from the binding of antibodies to antigens
    Agglutination, opsonization, neutralization, complement activation - cell lysis, antibody-dependent cell-mediated cytoxicity
  102. A vaccine that contains a weakened microorganism and provides lifelong immunity is called
    Attenuated vaccine
  103. A vaccine that contains antigenic fragments of a microbe is called
    Subunit vaccine
  104. Monoclonal antibodies are derived from a plasma cell fused to a myeloma cell
  105. Precipitation reactions depend on the optimal proportion of antibody and antigen
  106. Blood typing is performed using what type of reaction
  107. Anaphylactic reactions involve the binding of IgE antibodies to which cells
    Mast cells and basophils
  108. Rejection of a blood transfusion is a result of what kind of hypersensitivity reaction?
  109. To avoid rejection, tissues are matched based on what?
    Blood type and HLA type
  110. Autoimmune diseases arise from a loss of tolerance to normal microbiota
  111. HIV is able to evade the immune system by infecting and depleting
    CD4+ T cells
  112. The urinary bladder and upper urinary tract are normally sterile
  113. A disease that is contracted by contaminated urine from dogs and rats
  114. Bacteria vaginosis is diagnosed by
    Increased pH and clue cells
  115. An STI that produces 4 distinct stages of infection is
  116. A disease in women that can lead to blocked uterine tubes and terility
    Pelvic inflammatory disease
  117. A highly contagious rash caused by Staphylococcus aureus entering the skin is
  118. Pediculosis is a disease caused by
  119. Human Parvovirus B19 is the causative agent of which disease?
    Fifth Disease
  120. Variola virus is the causative agent of which disease?
    Small pox
  121. Antibiotics would be helpful in treatment of which of the following disease?
    Necrotizing fasciitis
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Microbiology Exam #4
2014-05-10 22:23:36

Microbiology Exam #4
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