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171 Cards in this Set
- Front
- Back
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Two arms of immunity
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Innate, Adaptive
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Innate immunity:
First line of defense |
Skin,
Mucous membranes Normal microbiota |
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Innate immunity:
Second line of defense |
Phagocytes-neutrophils, eosinophils, dendritic cells, macrophages
Inflammation Fever Antimicrobial substances |
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Innate immunity
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Nonspecific immunity
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Ex of Phagocytes
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neutrophils, eosinophils, dendritic cells, macrophages
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Adaptive immunity:
Third line of defense |
Resistance to a specific pathogen
Specialized lymphocytes: T cells, B cells Antibodies |
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Immunity
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ability to ward off disease
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Innate immunity:
First line of defense Physical Skin inhibits bacterial growth |
Oils have defensins targeting against bacteria, viruses
High salt content Lysozyme Fatty acids, inhibit some pathogens but acts as nutrients for others |
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Innate immunity:
First line of defense Physical Mucus |
Mucus traps microbes
Ciliary escalator transports microbes away from lungs |
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Innate immunity:
First line of defense Physical Secretions |
Lacrimal aparatus-washes eyes
Saliva-low pH, lysozyme, urea; washes microbes off Urine-low pH, lysozyme, urea; defecation, vomiting-flows out Vaginal secretions-low pH, flows out |
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Innate Immunity
First line of defense Normal microbiota |
Compete with pathogens or alter environment
Environment hostile to other bacteria |
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Innate Immunity
Second line of defense Cardiovascular |
Cardiovascular-blood sterile due to macrophages, low iron
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Innate Immunity
Second line of defense lymphatic system |
Lymphatic-collects fluid to tissue, feeds back to heart
Lymph nodes-fluid is fed through, has B cells, T cells to clean fluid Phagocytic cells |
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Lymphatic system
Phagocytosis |
Neutrophils-1st response
Monocytes-leave blood, become macrophages, 2nd response Fixed macrophages-resident in tissue/organ Wandering macrophages-gather at infection |
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Innate system activators
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Toll like receptors (TLRs)
Attach to pathogen associated molecular patterns Induce defensive cells to release cytokines, regulate immune responses |
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Cytokines
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Protein produced by all cells of the immune system in response to a stimulus
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Interferons
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Cause cells to produce antiviral proteins that inhibit viral replication
Causes neutrophils and macrophages to phagocytize bacteria |
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Innate Immunity
Second line of defense Formed elements in the blood |
Red blood cells, natural killer cells, platelets, Dendritic cells
WBCs (leukocytes), neutrophils, monocytes, Basophiles, Eosinophils, lymphocytes |
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Red blood cells
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transport O2 and CO2
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WBCs (leukocytes), neutrophils-
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phagocytosis, motile (leave blood)
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Granulocytes
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neutrophils, basophiles, eosinophiles
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Basophiles,
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histamine, inflammation and allergic responses
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Eosinophils
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Kill parasites
Phagocytosis, leave blood, produce toxins |
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Dendritic cells
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phagocytosis
Initiate adaptive immunity Abundant in epidermis, mucous, thymus, lymph |
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natural killer cells
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Also T cells, B cells
Adaptive immunity Destroy target cells, not bacteria |
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platelets
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Blood clotting
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WBCs (leukocytes) monocytes
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phagocytosis after leaving blood
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Most of white blood cells
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60-70% are neutrophils
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Fever
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Gram - endotoxin cause phagocytes to release interleukin 1
Hypothalamus releases prostaglandins that reset hypothalamus to high temperature |
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Fever advantages
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Increases transferrins
Increases interleukin 1 (IL-1) Produces Interferon |
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Fever disadvantages
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Tachycardia
Acidosis Dehydration High temperatures can be fatal |
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Tachycardia
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fast heart beat
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Acidosis
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excessive acid in body processes
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3 pathways for activating complement
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Classical
Alternative Lectin |
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Complement
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Serum proteins activated in cascade
Activated by: Antigen-antibody reaction Proteins C3, B, D, P, pathogen |
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C3b causes
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opsonization
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C3a + C5a cause
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inflammation
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C5b + C6 + C7 + C8 + C9 cause
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cell lysis
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Bacteria evade complement
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Capsules prevent C activation
Surface lipid-carbs prevent membrane attack complex formation Enzymatic digestion of C5a |
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Transferrins
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bind serum iron
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Siderophores
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parasite uses to bind iron
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Sepsis
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infection of blood
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Microbial evasion of phagocytosis
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Inhibit adherence
Kill phagocytes Lyse phagocytes Escape phagosome Prevent phagosome-lysosome fusion Survive in phagolysome |
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M protein, capsules
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Inhibit adherence
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Kill phagocytes
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leukocidins, streptolysin
Release lysosome into cytoplasm |
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Lyse phagocytes
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membrane attack complex
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Gram + sepsis
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Endotoxin shock
-Blood pressure decreases -Antibiotics worsen condition, kill bacteria |
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Activation of B cells
T-dependent |
Antigens on B cell, combines with MHC II
MHC II- antigen displayed on cell T helper cell recognize complex, release cytokines to activate B cell B cell differentiates to memory and plasma cells Plasma cells-antibodies in blood stream |
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How do antibodies protect against foreign substances
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Agglutination, opsonization, neutralization, activation of complement, antibody-dependent cell mediated cytotoxicity
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Agglutination
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reduces number of infectious units
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Opsonization
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coating antigen with antibody enhancing phagocytosis
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Neutralization
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blocks adhesion of bacteria, viruses to mucosa
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Activation of complement
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inflammation, cell lysis
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Antibody-dependent cell mediated cytotoxicity
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antibodies attached to target cell cause destruction by macrophages, eosinophils, NK cells
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Types of immunization
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naturally acquired
artificially acquired |
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Types of immunization
naturally acquired |
Active- recovery from infection
Passive- maternal antibodies |
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Types of immunization
artificially acquired |
Active- vaccination
Passive- injection of preformed antibodies |
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Attenuated vaccine
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in lab, cultured to lose pathogenicity or remove genes
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Inactivated whole-agent vaccines
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killed microbes
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Toxoids
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require boosters, small amounts of toxin
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Subunit vaccines
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just parts of microbe, only have antibodies against specific part
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Nucleic acid vaccines
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DNA vaccines
DNA injected, transcribed, and translated |
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Activation of B cells
T-independent antigens |
Stimulate B cell to make antibodies
Repetitive can bind many B-cell receptors at once to activate |
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Most effective vaccines, why
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Attenuated
Larger response Reproduce in cells-T cytotoxic cells T cytotoxic cells form memory cells |
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Development of new vaccines
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Culture pathogen
rDNA techniques Deliver in combination Adjuvants-modifies effect of other agents, large response |
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Risks from vaccines
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Extremely rare, unpredictable
Far lower than chances of getting disease |
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Antibodies
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produced by B cells
Most have 2 antigen binding sites Y shape |
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Monoclonal antibodies (Mabs)
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take parent cell, clone it
take substrate, cloned cells make clones of antibodies that bind to substrate can purify/detect substance |
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Sensitivity
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probability test is reactive with a true positive
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specificity
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probability test will not be reactive with true negative
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Western blot
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gel separates proteins
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Direct ELISA
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Direct enzyme linked immunosorbent assay
Antibody in well Patient sample put in Antigen binds to antigen Enzyme the antibody is specific for added, binds to antigen Enzyme substrate added, reaction changes color of product |
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Fluorescent antibody technique
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antibodies linked to fluorescent dye
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Antibody titer
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concentration of antibodies against a particular antigen
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Hemagglutination
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agglutination of RBCs
Some viruses agglutinate RBCs in vitro Antibodies prevent agglutination |
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Indirect ELISA
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Enzyme linked immunosorbent assay
Antigen in well Patient serum added Antibody binds to antigen Enzyme added, binds to bound antigen Enzyme substrate added, reaction has color change |
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ID50
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Infectious dose for 50% of the test population
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LD50
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Lethal dose for 50% of test populations
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Parenteral Route
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When skin or mucous membranes are penetrated or injured
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Most microbes enter through
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Gastrointestinal and respiratory mucous membranes
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Penetration or evasion of host defenses
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Capsules
Cell Wall components Enzymes Antigenic variation Invasins Intracellular growth |
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Damage to host cells
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Toxins-endo, exotoxins
Lysogenic conversion Waste products Use host nutrients (Siderophores) Disrupt cell function |
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Portals of exit
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Generally similar to portals of entry for microbe
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Adherence
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Adhesins/ligands bind to receptors on host cells
Glycocalyx, fimbriae, M protein-inhibit adherence Often receptors are made of sugars Sometimes creates biofilm |
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Penetration or evasion of host defenses
Capsules |
Prevent phagocytosis
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Penetration or evasion of host defenses
Cell Wall components |
M protein resists phagocytosis
Fimbrae and Opa protein-attach to host cells and get imported Mycolic acid-resists digestion |
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Penetration or evasion of host defenses
Antigenic variation |
alter surface proteins
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Antigenic shift-
Antigenic drift |
changes in HA, NA spikes
Genetic recombination between different strains infecting cell Point mutations in genes encoding HA or NA spikes Allows virus to avoid IgA antibodies |
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Penetration or evasion of host defenses
Enzymes |
Coagulase
Kinases Hyaluronidase Collagenase IgA proteases |
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Coagulase
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coagulates fibrinogen into fibrin
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Kinases
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digest fibrin clots
Catalyze substrate level phosphorylation to make ATP |
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Hyaluronidase
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hydrolyzes hyaluronic acid, component of connective tissue
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IgA proteases
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destroy IgA antibodies
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Penetration or evasion of host defenses
Cytoskeleton |
Invasins
Actin to move from one cell to the next |
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Exotoxin
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toxin excreted by microorganism
Membrane disrupting or superantigen Gram positive Neutralized by antitoxin Small LD50 Protein |
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Endotoxin
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toxin that is a structural molecule of the bacteria that is recognized by the immune system
Gram negative Outer membrane--LPS layer Large LD50 |
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A-B Exotoxin
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B binds cell receptor
A-B Toxin taken up by endocytosis A-B in cytoplasm through pinocytosis A and B dissociate, A is toxin |
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Membrane disrupting exotoxins
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Lyse host cells
-Make protein channels in plasma membrane -Disrupt phospholipid bilayer |
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Superantigen exotoxins
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Intense immune response
Release of cytokines from immune cells (T cells) |
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LAL Assay
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Detects endotoxins
Limulus amoebocyte lysate assay |
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Pathogenic properties of Fungi
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Fungal waste may cause symptoms
Chronic infections-allergic reaction Toxins inhibit protein synthesis Proteases (digest protein) Capsule prevents phagocytosis |
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Pathogenic properties of protozoa
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Waste products cause symptoms
Avoid host defenses by: -Growing in phagocytes -Antigenic variation |
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Pathogenic properties of helminths
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Use host tissue
Presence of parasite interferes with host function Metabolic waste cause symptoms |
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Portals of Exit
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-Similar to entrance
Respiratory tract GI tract Genitourinary tract (urine, vaginal secretions) Skin Blood |
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1 millimeter (mm) =
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10-3 meter
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1 micrometer (mm) =
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10-6 meter
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1 nanometer (mm) =
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10-9meter
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1 picometer (mm) =
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10-12meter
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Refractive Index
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the speed of light in a particular substance as compared to a vacuum
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Resolution
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ability of lenses to distinguish two points
Shorter wavelengths=greater resolution Max resolution is 1000X |
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Compound light microscopy
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Image from objective magnified by ocular
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Total magnification
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Objective X Ocular lens
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Light Microscopy
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Use of any kind of microscope that uses visible light to observe specimens
Brightfield (compound light microscopy), darkfield, phase-contrast, fluorescence, confocal |
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Darkfield Microscope
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excludes the light that is unscattered
Black background |
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Phase contrast
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Small phase shifts in light passing through transparent specimen converted to amplitude or contrast changes in image
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Fluorescence microscope
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Fuse protein of interest to a fluorescent protein
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Fluorescence
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ability of substance to absorb short wavelengths of light (UV), give off light at a longer wavelength (visible)
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Confocal Scanning Laser Microscope
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Computer 3D images
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Smear
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thin film of solution of microbes on slide
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Fixed smear
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Fixed by alcohols or heat
Kills microbes |
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Simple staining
Acidic dye Basic Dye |
Acidic dye - charge
Basic Dye + charge |
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Gram stain
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Crystal violet - iodine - alcohol - safranin
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Acid fast cell walls
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Like gram positive
Waxy lipid |
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Mycoplasmas cell walls
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lack cell walls
Sterols in plasma membrane |
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Archaea cell walls
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Wall less or
Walls of pseudomurein (lack NAM, D-amino acids) |
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Acid fast stain colors
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Acid fast: red
Non-acid fast: blue |
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Endospore staining
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Malachite green, heat
Decolorize-water Counterstain-safranin |
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Electron microscope
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Observing internal features of cells
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Atomic force microscope
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High resolution
Can see structure of molecules |
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“Metabolism:
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The sum of the chemical reactions in an organism”
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Why do cells perform chemical reactions?
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Division
-Replicate DNA, split DNA, form cross wall |
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Heterotrophy
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get building blocks, matter from organic nutrients
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Autotrophy
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get building blocks, matter from CO2 and inorganic energy source
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Laws of Thermodynamics
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Energy not created or destroyed
Systems tend towards disorder |
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Collision theory
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Chemical reactions occur when atoms, ions, molecules collide
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Exergonic
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Products have less energy than reactants
Spontaneous |
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Four principles of metabolism
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Chemical reactions catalyzed by enzymes
Reaction coupling Redox reactions are how energy is harvested Biological membranes transduce energy into useful forms |
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Enzyme catalysts
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bring reactants together in the right geometry
lowers activation energy |
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Apoenzyme
Coenzyme Holoenzyme |
Protein portion-Inactive
Cofactor-nonprotein portion- activator Whole enzyme- active |
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Factors influencing enzyme activity
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Temperature and pH denatures proteins
Optimal temperature, pH ranges Increasing substrate concentration increases enzymatic activity |
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Many antibiotics work by inhibiting
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Cell's enzymes
Inhibit cell wall biosynthesis Inhibiting translation (ribosomes) Inhibit metabolic pathways Inhibit DNA/RNA synthesis |
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Enzyme inhibitors (2 types)
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Competitive inhibition
Non-competitive inhibition |
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Endergonic
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Requires energy for reaction
Nonspontaneous |
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Chemical reactions in cells are performed to
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Obtain energy
Obtain carbon, transform it into cellular constituents |
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Anabolic reactions
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Build things up
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Catabolic reactions
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Break things down
Break down carbohydrates, release energy, store as ATP/NADH Glycolysis, Krebs cycle, electron transport chain |
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ATP generated by
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Phosphorylation of ADP
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glycolysis:
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glucose is converted to pyruvate.
Two ATP and NADH are derived. 6 essential precursors are made per glucose. |
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TCA:
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6 NADH, 3 essential precursors, 2 ATP
Constant cycling AKA Krebs cycle |
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pentose phosphate:
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2 NADPH (plus it then makes more as it joins into glycolysis),
3 essential precursors for making ribose. |
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Redox reactions
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Energy harvested, transferred to a new reaction
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NAD+ to NADH
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Needs H+ and 2e-
Accumulates energy in a usable form |
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intermediate step:
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pyruvate to acetyl coA:
one essential precursor is made plus two NADH per glucose. |
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Respiratory Electron Transport System
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Electrons from NADH -> O2 release energy
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Anaerobic respiration
Denitrification |
NO3 to N2 gas
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Fermentation
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Oxidizes NADH to NAD+ to allow glycolysis under anaerobic conditions
No Krebs cycle or ETC Organic molecule as final electron acceptor |
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Photosynthesis reactions
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Heterotrophs get complex carbon
6CO2 + 12H20 + Light -> Glucose + 6H2O + 6O2 6CO2 + 12H2S + Light -> Glucose + 6H2O + 12S |
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Light dependent reactions
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Photosynthesis
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Carbon fixation
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Fixing carbon into organic molecules
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Light independent reactions
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Calvin Benson cycle
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Principles of Photosynthesis
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Photochemistry in a lipid bilayer
Energy absorbed by antenna pigments on or in membrane Energy transferred through antenna to a reaction center where photochemistry occurs |
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Green plant photosynthesis
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2 Light reactions connected in series
PhotosystemII - Cytochrome - PhotosystemI Electron flow is linear |
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Cyclic photophosphorylation
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Only uses light reaction
Makes ATP |
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Noncyclic photophosphorylation
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Uses dark reaction
Makes ATP, NADPH |
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Dark reaction
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Fixing CO2
Calvin cycle Plants and bacteria--autotrophy |
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Rubisco
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enzyme performing Dark reaction
Inefficient, packed in carboxysomes |
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Classification of organisms
Most bacteria and all fungi, protozoa and animals |
Chemotrophs
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3 ways making ATP
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Substrate level phosphorylation
Oxidative phosphorylation Photophosphorylation |
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Effects of viruses
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Cease function
Fusion of infected cells Release immune-suppressing substances Produce interferons Antigenic changes signals immune system Chromosomal changes in host cell Cancer causing |
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Vaccines
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First time IgM
Second time IgG |
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MHC II vs MHC I
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MHC II-APC cells, displays external proteins
MHC I- displays internal proteins, ex viral infection |
