MICROBIO 4000 EXAM 4 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

MICROBIO 4000 EXAM 4 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 immunity - Answers ability to ward off disease cause by microbes and their products and protect against environmental agents susceptibility - Answers lack of immunity pattern recognition receptors (PRRs) - Answers recognize elements frequently found of microbes but different from the host toll like receptors (TLRs) - Answers one class of PRRs on host that recognize PAMPs cytokines - Answers proteins that regulate the intensity and duration of immune responses two types of immunity - Answers innate and adaptive innate immunity - Answers more general, defenses from birth, provides rapid response, doesn't recognize specific microbes, no memory response, 1st and 2nd lines of defense adaptive immunity - Answers acquired, slower to respond, specific responses to microbes, memory component, 3rd line of defense basics of innate immunity - Answers 1. activated by protein receptors in the plasma membrane of defensive cells 2. TLRs attached to components commonly found on pathogens called PAMPs 3. TLRs bound to PAMPs induce the release of cytokines from the host cell epidermis - Answers out, thinner portion of skin keratin - Answers protective protein dermis - Answers inner, thicker portion of skin, made of connective tissue mucus membrane - Answers epithelial layer and underlying connective tissue that line the GI, respiratory, and GO tracts normal microbiota - Answers microorganisms that establish a residence but don't produce disease under normal conditions prebiotics - Answers chemicals that selectively promote the growth of beneficial bacteria probiotics - Answers live microbial cultures administered to exert a beneficial effect first line defenses - Answers physical barriers, chemical factors, normal microbiota purpose of physical barriers - Answers block entry of microbes, largest are skin and mucus membranes physical barriers: skin - Answers - largest organ - epidermis is in direct contact with outside environment, dead, contains keratin, tightly packed - dermis how does the skin act as a physical barrier? - Answers prevents entry via arrangement and structure, shedding of dead cells, tightly packed physical barrier: mucus membrane - Answers secrete mucus (glycoprotein) that prevents tracts from drying out and helps trap microbes physical barrier: ciliary escalator - Answers transports microbes trapped in mucus away from lungs physical barrier: lacrimal appartus - Answers drains tears, washes eyes physical barrier: saliva - Answers dilutes and washes teeth physical barrier: earwax - Answers prevents microbes from entering ear physical barrier: urine - Answers cleans out urethra via flow physical barrier: vaginal secretions - Answers move microbes out of vaginal tract physical barrier: epiglottis - Answers prevents microbes from entering lower respiratory tract when swallowing physical barrier: others - Answers peristalsis, defecation, vomiting, diarrhea commonality of chemical factors - Answers most involves lysozyme which destroys bacterial cells and acidic pH which inhibits microbial growth chemical factors: sebum - Answers comes from the sebaceous gland and forms a protective film. fatty acids lower pH (3-5) of skin and unsaturated fatty acids inhibit growth chemical factors: earwax - Answers fatty acids and sebum in earwax lower pH chemical factors: saliva - Answers contains lysozyme, uric acid, urea, and is slightly acidic (6.55-6.85) chemical factors: gastric juices - Answers HCl, enzymes, and mucus that are highly acidic and destroy most microbes chemical factors: vaginal secretions - Answers low pH and inhibit microbes. cervical mucus has antimicrobial properties chemical factors: urine - Answers lysozyme and acidic pH normal microbiota: competitive exclusion - Answers adapted for living where they live and have a competitive advantage over pathogenic bacteria normal microbiota: produce substances - Answers inhibit or kill other bacteria normal microbiota: building an immune system - Answers dependent on microbiota types of second line defense - Answers defensive cells (phagocytic cells), inflammation, fever, antimicrobials pluripotent stem cells - Answers stem cells capable of giving rise to several different cell types neutrophil: main function and type of immunity - Answers phagocytosis (highly), innate immunity T cells: main function and type of immunity - Answers cell-mediated immunity, adaptive immunity eosinophils: main function and type of immunity - Answers parasite and some phagocytosis, innate immunity macrophage: main function and type of immunity - Answers phagocytosis, innate immunity natural killer cells: main function and type of immunity - Answers destroy abnormal cells by cytolysis and apoptosis, innate immunity platelets: main function and type of immunity - Answers blood clots, (innate) B cells: main function and type of immunity - Answers produce antibodies, adaptive immunity mast cells: main function and type of immunity - Answers similar to basophils (histamine), innate immunity monoctyes: main function and type of immunity - Answers immature macrophage, innate immunity basophils: main function and type of immunity - Answers histamine and no phagocytosis, innate immunity erythrocytes: main function - Answers carry O2 and CO2 dendritic cells: main function and type of immunity - Answers phagocytosis and initiate the adaptive immune response, innate immunity which cells are leukocytes? - Answers all but platelets and erythrocytes which cells have a myeloid precursor? - Answers neutrophils, eosinophils, platelets, mast cells, basophils, and erythrocytes which cells have a lymphoid precursor? - Answers t cells, natural killer cells, and b cells which cells have a monocyte precursor? - Answers macrophage and dendritic cells which cells are granular? - Answers neutrophils, eosinophils, mast cells, and basophils which cells are agranular? - Answers t cells, macrophages, natural killer cells, b cells, monocytes, and dendritic cells which cells make up a majority of the WBC count? - Answers neutrophils because they are the first at an infection site phagocytosis - Answers ingestion of a microorganism or other substance by a cell phagocytes - Answers cells that perform phagocytosis which cells are dominant in an early infection vs later infection? - Answers neutrophils are dominant phagocytes in early infection, as infection progresses macrophages dominate fixed macrophages vs wondering macrophages - Answers reside in particular tissues while the wondering roam and gather at sites of infection four main phases of phagocytosis - Answers 1. chemotaxis 2. adherence 3. ingestion 4. digestion mechanism of phagocytes - Answers 1. chemotaxis: microbial products and damaged tissue cells release chemical signal and WBC release cytokines 2. adherence: PAMPs bind to TLRs, opsonization occurs 3. ingestion: pseudopods surround microbe, fuses with vesicle to form phagosome 4. digestion: fusion with lysosome to form phagolysosome, pumps in protons and enzymes, ingestible materials form residual body, discharged out of cell inflammation - Answers a local defense mechanism that can be triggered by microbes, physical or chemical agents. function is to destroy injurious agent and remove it or limit spread signs and symptoms of inflammation - Answers pain, redness, immobility, swelling (edema), heat vasodilation - Answers dilation of blood vessels which causes redness and heat increased permeability - Answers defensive substances can leave blood vessels and enter injured area. also causes edema two types of inflammation - Answers acute and chronic acute inflammation - Answers - rapidly develop - last short period (days-weeks) - mild self-limiting - neutrophils principal mechanism chronic inflammation - Answers - slower developing - last longer period (months to years) - severe and progressive - monocytes macrophages process of inflammation - Answers 1. damaged cells release chemicals which cause vasodilation and permeability of blood vessels 2. blood clot forms and prevents spread of agent 3. margination: blood flow decreases and neutrophils + monocytes migrate to area and stick to lining of vessel 4. diapedesis: phagocytes squeeze thru blood vessel walls 5. phagocytes destroy via phagocytosis 6. tissue repair histamines - Answers vasodilation, increased permeability of blood vessels kinins - Answers vasodilation and increased permeability; chemotaxis of neutrophils prostaglandins - Answers intensifies histamines and kinin response; helps phagocytes move through capillary walls; associated with pain leukotrienes - Answers increased permeability; help phagocytes attach to pathogen cytokines in inflammation - Answers produced by fixed macrophages; vasodilation and increased permeability of blood vessels, chemotaxis of phagocytes and adaptive immune cells fever - Answers - systemic response of abnormally high body temp - facilitated by cytokines (IL-1, TNF-a) cause hypothalamus to release prostaglandins which increase body temp - speed up growth of bacteria, speed up rxns, speed up antiviral interferons, decrease iron for microbes, helps increase T cell types of antimicrobial substances - Answers complement system, interferons, iron binding proteins, antimicrobial products complement system - Answers - 30+ proteins produced by the liver that enhances cells of immune system in destroying microbes - innate but can be turned on by adaptive immune system - inactive until split into fragments three pathways of complement system - Answers classical, alternative, lectin classical pathway - Answers 1. antibody attach to antigen and activates C1 2. C1 activates C2 and C4 3. C2 and C4 split into a and b 4. C2a and C4b combine and activate C3 5. C3 splits into a and b alternative pathway - Answers 1. C3 combines with complement protein factors B, D, and P at microbes surface 2. C3 splits into C3a + C3b lectin pathway - Answers 1. mannose binding lectin (opsonin) bind to carbs on microbe which activates C2 and C4 2. C2 and C4 split into a and b 3. C2a + C4b combine and activate C3 4. C3 splits into a and b three outcomes of complementation - Answers cytolysis, opsonization, inflammation cytolysis pathway - Answers 1. C3b activates C5 2. C5 splits into a and b 3. C5b activates C6 4. C6-9 combine to form MAC