Microbiology Final Exam Study Guide – Flashcards
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list the steps of a gram stain in order
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1) crystal violet is applied to heat fixed smear 1 min. this stains all cells, called a primary stain. rinse w/ water 2) an iodine mordant is added; 1 min, rinse 3) wash with ethanol (some species of bacteria are decolorized and some are not. if smear retains purple dye, organism is gram positive. if alcohol removes the dye, organisms are no longer visible.) 4) safrinin is used as a counterstain. it is applied and the decolorized bacteria are visibly red. these are gram negative.
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what are the two possible responses of a gram stain?
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gram positive-crystal violet and gram negative-safrinin. the gram stain reflects a basic difference in the cell wall structure of bacteria. it is the first step in identification and the susceptibility of miocroorganisms to antibiotics is often related to the gram reaction.
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will retain crystal violet dye and become purple. peptidoglycan layer is thick.has many teichoic acids. has no periplasmic space. has no outer membrane. has little to no LPS content. has low lipid and lipoprotein content because acid fast bacteria have lipids linked to peptidoglycan. has 2 flagellar rings in basal body. produces exotoxins. has very high resistant to physical disruption. has a high cellwall disruption by lysozyme. susceptible to penicillin and sulfonamide. not susceptible to streptomycin, chloramphenicol, and tetra cycline. highly inhibited by basic dyes.highly susceptible to anionic detergents. highly resistant to sodium azide. resistant to drying.
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gram positive
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can be decolorized to accept the counterstain safranin and stain pink/red.peptidoglycan layer is thin. has no teichoic acids. has periplasmic space. has outer membrane. has high LPS content. has high lipid and lipoprotein content because of the presence of the outer membrane. has 4 flagellar rings in basal body. produces endotoxins and exotoxins. has very low resistance to physical disruption. has a low cell wall disruption by lysozyme because it requires pretreatment to destabilize the outer membrane. not susceptible to penicillin and sulfonamide. susceptible to streptomycin, chloramphenicol, and tetra cycline. not inhibited by basic dyes. not susceptible to anionic detergents. susceptible to sodium azide. susceptible to drying.
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gram negative
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what is the best microscope for biofilms?
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scanning acoustic
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which microscope has the highest magnification?
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transmission electron microscope. 10,000x-100,000x
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microbial communities that reside in a matrix called slime made of hydrogel. enable bacteria to share nutrients and shelter them from drying and other harmful environmental factors. play an important role in the digestive system of ruminants. 70% of all human infections involve this. and these are 1,000 x more resistant to antibiotics than normal bacteria. pass around antibiotic resistance (DNA) through conjugation. they especially infect humans through nosocomical infections from indwelling medical devices like catheters and ventilators. everything has biofilms on it but it becomes dangerous and an infection when it gets inside the body
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biofilms
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pts with catheters are at risk because of what?
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biofilms
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Nutritional type: Chemoheterotroph,ATP Cellular Arrangement: Multicellulare, has tissues and organs Food Acquisition Method: Ingestion/absorbtion Charecteristic features: elaborate reproductive system; transmitted via ingestion.
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helminths
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HSV1 and HSV2(cold sores), HTLV1 and HTLV2(Luekemia), and Varicellovirus(shingles) are examples of this type of virus
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latent viruses
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HIV1 and HIV2/AIDS, HPV(cervical cancer),measles(SSPE), HBV(Hepatitis B virus) are examples of this type of virus
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persistent viruses
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Koch's postulate is used to prove _______________
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the CAUSE of infectious disease. *important to note that not all diseases are caused by microoganisms therefore this method cannot be used to find the cause to all infectious diseases.*
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the study of WHERE and WHEN diseases occur and HOW they are transmitted. Center for Disease and Control (CDC) collects data and it is published in the Morbidity and Mortality Weekly
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epidemiology
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disease that is constantly present in a population(ex: common cold)
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endemic
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disease acquired by many hosts in a given area in a short time(ex: Influenza).
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epidemic
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worldwide epidemic.(ex: AIDS, FLU H1-N1)
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pandemic
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infections that are acquired as a result of hospital stay. Affect 5-15% of all hospital patients. In order for a nosocomial infection to develop, 3 things must be present: 1.)microorganisms in a hospital environment 2)compromised host 3)chain of transmission
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nosocomial infections
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what is the major component of the plant cell wall?
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cellulose
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what is the major component of the fungi cell wall?
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chiton
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what is the major component of the bacterial cell wall?
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peptidoglycan. ***note: pseudomurein for archaea****
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what is peptidoglycan made of?
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NAG and NAM
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has a thick waxy wall
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mycobacterium
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has no cell wall
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mycoplasma
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animal cells and protozoa have __________
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no cell wall
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most common bug to cause food spoilage in terms of temperature. 10-50 degrees Celsius. room temp
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mesophile
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-10-20 degrees celsius
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psychrophiles
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0-30 degrees celsius
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pyschrotrophs
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40-70 degrees celsius
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thermophiles
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67-110 degreees celsius
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hyperthermophiles
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what group would you expect penicillin to be uneffective against?
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mycoplasmas. because they have no cell wall
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biofilms are _____________
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1,000x more resistant to microbicides. 70% of human infections associated with biofilms
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which cell wall is sensitive to penicillin?
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gram positive. no porin protein like gram negative has. penicillins prevent the cross-linking of the peptidoglycans, which interferes with the final stages of the construction of the cell walls.
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what is the difference between bacteria and viruses?
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viruses are not cells; bacteria are. bacteria are treated with antibiotics; viruses arent. viruses are obligate intracellular and they have DNA or RNA but never both and they all have a protein coat that surrounds the nucleic acid-capsid.
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contain and envelope around the outside of the genetic material and the capsid. ex. influenza
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enveloped viruses
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virus structure that contains capsomere, Nucleic acid, and capsid and lack envelope.
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polyhedral viruses
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virus structure with a virion, and in addition having feet like apparatus to help inject its genetic material into the host cell. has spikes for attachment
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complex viruses
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virus structure that contains a cylindrical capsid with helical/spiral genetic information
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helical viruses
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why are cancers hard to link to viruses?
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most particles of some viruses do not induce cancer. Don't develop until long after the viral infection. Cancers do not seem to be contagious and viral diseases usually are.
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viruses that infect without causing symptoms
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subclinical
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virus cylce where virus infecs host and does not destroy cell when released
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lysogenic cycle
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Source: Mostly Gram + Relation to Microbe: by products of growing cell Chemistry: Protein Fever: NO Neutralized by Antitoxin: YES LD50: small
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exotoxin
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Source: Gram - Relations to Microbe: outer membrane Chemistry: Lipid A and LPS Fever: YES Neutralized by Antitoxin: NO LD50: Relatively Large ****role: cause DECREASED BP*****
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endotoxin
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take iron from host cells. Protein that bacteria release that can bind to iron and take it away(compete w/ tranferin iron complex[keeps iron for you] )
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siderophore
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defenses we are born w/;rapid; always there
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innate immunity
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virus cycle that ends with the death of the host cell as the virus is released
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lytic cycle
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stage of cycle wherre phage attaches(chance collision)by tail fibers to host cell
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Attachment(Lytic Cycle)
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stage of cycle where phage lysozyme opens cell wall; tail sheath contracts to force tail core and DNA into cell.
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Penetration(Lytic Cycle)
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stage of cycle where there is production of phage DNA and proteins using the host cell's ribosomes, enzymes, and amino acids.
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Biosynthesis(Lytic Cycle)
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stage where assembly of phage particles takes place
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Maturation(Lytic Cycle)
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stage where phage Lysozyme breaks cell wall
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Release(Lytic Cycle)
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fraction of a population that contracts a disease DURING A SPECIFIC TIME.
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incidence
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change in body fxn that is felt by a patient as a result of a disease(subjective)(what patients tell you)ex: pain and malaise
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symptoms
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a change in a body that can be measured or observed as a result of disease (objective) ex: fever, rash, swelling, paralysis.
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signs
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which WBC has the highest phagocytic activity?
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neutrophils
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which WBC is associated with parasites?
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eosinophils
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Nutritional Type: Chemoheterotrophic Cellular arrangement: unicellular, multicellular, filamentous, fleshy Charecteristics: Fungi are classified according to sexual and asexual spores. Fungi grow in HIGH osmotic pressure, LOW pH, and LOW moisture environments. human pathogens: YES Food source: Organic
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fungi
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Phagocytes squeeze between endothelial cells
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diapedesis
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Phagocytes stick to endothelium
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margination
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Order of bacteria that has efflux pumps, Responsible for 10% of Nosocomial infections. on soil and plants. cystic fibrosis patients are susceptible to this.
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pseudomonales
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what is unusual about caulobacter?
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it is a bacteria that is stalked for increased nutrient absorption. occurs in low nutrient environments such as lakes.
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what are yeast infections caused by?
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candida albicans
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antigens on a cell(ex:blood typing)
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direct aggultination
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use living organism but weakened microbes; provides long lasting lifetime immunity derived from mutations accumulated during long term artificial culture; not recommended for patients with weakened immune systems(ex: measles, mumps, rubella, chickenpox)
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attenuated whole agent vaccine
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uses microbes that have been killed, usually by Formalin or Phenol. (ex: rabies, influenza, and salk polio)
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inactivated whole agent vaccine
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use only those antigenic fragments of a microorganism that best stimulates an immune response; inherintly safer because they cannot reproduce in the recipient; fewer side effects(B. Pertussis)
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sub unit vaccine
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used in new Hep B.; consists of a portion of the viral protein coat that is produced by genetically modified yeast.
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recombinant vaccine
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developed in recent years to deal with the poor immune responses of children to vaccines. based on capsular polysaccharides. These are combined with toxoid leading to a very successful vaccine such as H Flu Type B even at 2 mnths.
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conjugated vaccine
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this vaccine Uses DNA insterted into plasmids
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nucleic acid vaccine
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particular antigens
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agglutination
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soluble antigens
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precipitation
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cause the unpleasant and damaging effects of an allergic reaction(histamine,leukotrienes, and prostaglandin)
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mediators
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mediator that causes swelling, mucous secretion, tightening of airway, increase of permeability of blood capillaries
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histamine
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mediator; effect is the longest and takes longest to release
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prostaglandin
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mediator; longer reacting; slower to happen
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leukotrienes
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process that releases mediators; mast cells and basophils undergo this.
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degranulation
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-occur within 2-30 min after re exposure to antigen -can be systemic or localized -IgE attached to Mast cells and Basophiles -Antigen binds to two adjacent IgE -Mast cell and basophils undergo degranulation which release mediators(histamine,leukotrienes,and prostaglandin)
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anaphylactic reactions type 1
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reactions that are directed against antigens located on cell tissue surfaces. Involve IgG and IgM antibodies and complement. Complement activation cause cell lysis or damage by macrophages.(ex: blood typing)
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cytotoxic reactions type 2
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these reactions involve antibodies against soluble antigens circulating in the serum. Antigen AB complexes can be deposited in organs and cause damage. IgG antibodies and antigens form immune complexes-circulate in the blood-pass between endothelial cells of blood vessels and become lodged in basement membranes. Here they activate complement and may cause transient inflammatory reaction(ex: glomurulonephritis)
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immune complex reactions type 3
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involves cell-mediated immune responses. Delayed type hypersensitivities(DTH) due to T cells, not apparent for a day or more. Cytokines attract macrophages and t-cells(initiate tissue damage ex: transplant rejection, TB skin test, allergic contact dermatitis)
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cell mediated reactions type 4
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objective is to cause the production of IgG using INJECTIONS of ANTIGENS rather than IgE-hoping that the circulating IgG Abs will act as blocking Abs.
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desensitization
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what is the difference between natural penicillins and semisynthetic?
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part of the penicillin is produced by the mold and part is added synthetically. Nucleus is the natural part. side chains are synthetic.
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tine cruris
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jock itch
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list some antifungal drugs
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amphrotercerin B and Griseofulvin(both are types of Polyenes)
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what are the diseases that cross the placenta?
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toxoplasmosis, cytomegalovirus, and syphilis
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whats the treatment for bacterial vaginosis and trichinosis?
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metronidazole
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most common reportable disease in US
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gonorrhea
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major difference between rickettsias and chlamydias
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rickettsia has an insect vector.
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encysted larvae of tapeworms
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cysticerci
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binds to 50s portion of ribosome and inhibits formation of peptide bond(amino acids)*side affect: it can suppess bone marrow leading to aplastic anemia; potentially fatal* -also macrolides
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chloramphenicol
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changes shape of 30s portion of ribosome, causing code on mRNA to be read incorrectly. -aminoglycosides
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streptomycin
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(broad spectrum) interefere with attachment of tRNA to mRNA-ribosome complex which prevents the addition of amino acids to the growing protein chain. **serious side effect: cannot be used on children because it turn teeth brown. cannot be used on pregnant women because it can cause liver damage.**
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tetracycline
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generation of cephalosporins; narrow spectrum, gram+
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cephalosporins 1st
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generation of cephalosporins; extended spectrum includes gram-
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cephalosporins 2nd
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generation of cephalosporins; includes pseudomondales;injected; also oral
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cephalosporins 3rd
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generation of cephalosporins; injections, but have the most extended spectrum
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cephalosporins 4th
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inhibits cell wall formation earlier than Penicillin. Against gram+(staph and strept)
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bacitracin
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very important antibiotic. should be used as a last resort against MRSA. IV administered only. known as "The Big Boy".*VRE is considered a medical emergency.*
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vancomycin
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inhibit cell wall synthesis; consists of 4 generations. have beta lactam ring like penicillin which inhibits the replication of bacterial cell walls.
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cephalosporins
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all have beta lactum ring called the nucleus. A group of over 50 related chemicals. they differ by the side chains of the nucleus and prevent crosslinking of peptidoglycan of gram +. inhibits cell wall synthesis.
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penicillins
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the newest class of antibiotics. it binds to the 50s subunit which prevents translation by blocking the tunnel of the ribosome. best known is Erythromycin, but also includes azithromycin(which has the highest levels of resistance from overuse).
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macrolides
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broad spectrum, interferes with protein synthesis by changing the 30s subunit causing mRNA to be read incorrectly.**serious side effect: causes permanent damage to auditory nerve(ototoxic) and damage to kidney(nephrotoxic)**
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aminoglycosides
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inhibits mRNA synthesis. used in combo to treat tuberculosis. **serious side effect: turns saliva, urine, tears, sweat and feces orange.**
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rifampin
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topical application. treats gram(-) and is available over the counter. causes injury to the plasma membrane.
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polymixin B
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hese inhibit DNA gyrase activity. Drug of choice to treat urinary tract infections. common drugs on the market: Gatifloxacin, Gemifloxalin, moxifloxin & Ciprofloxcin. ***Cipro most common one used for UTI's & anthrax.
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quinolones and flouroquinolones
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Niclosamide - prevents ATP generation. used to treat tapeworms. Mebendazole - inhibits nutrient absorption in most intestinal worms. what type of drugs are these?
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antihelminth drugs
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why are helminthic diseases hard to treat?
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structurally & functionally similar to human cells, therefore hard to treat since medication can affect host.
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oxazolidinones(zyvox) prevents the formation of this ribosome?
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70s
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when altered this ribosome prohibits translation
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30s
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when altered this ribosome inhibits formation of peptide bond
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50s
