BIOS-242 Lab Practical Review Latest 2023 Graded A+

BIOS-242 Lab Practical Review Latest 2023 Graded A+ ________ and _____ ______ ______ are used to focus the microscope course and fine focus knobs _______ is where the specimen to be viewed is placed stage ______ ______ the primary optical lenses on a microscope. optical lens optical lens range from _X-_____X 4X-100X _______ is the light source for a microscope, typically located in the base of the microscope illuminator ______ connects to the base and supports the microscope head. It is also used to carry the microscope neck/arm ________ of the microscope supports the microscope and houses the illuminator base _______ _____-regular agar plate with added nutrients to promote growth nutrient agar plate ______- liquid medium lacks a solidifying agent broth _____- agar in petri dish and cooled this provides large surface areas for the isolation and study of microorganisms plate _____ _______- stain purple, have thick layer of peptidoglycan gram positive ______ _____- stain pink, contains much thinner layer of peptidoglycan gram negative shape: cocci round shape: bacillus long and skinny spirochete is _______ flexible spirillum is _____ stiff pleomorphic is ______ _____ multiple shapes _______ is long chains of cocci Streptococci _______ is long chains of bacillus streptobacilli ______ is clusters of cocci staphylcocci ______ is clusters of rods staphylobacilli ______ ______ (________)- carbolfuschin is primary dye- heat to drive stain inside acid fast (mycobacterium) ______ _____ (_______)- for bacteria with mycolic acid acid fast (mycobacterium) ______ (________)-background is dark, primary stain is eosin capsule (klebsiella) ______ (______)- thin hair like, hard to stain flagella () _________ (________ and _________)- malachite green , heat to drive stain inside endospore (clostridium and bacillus) ______ _____/ ____ ______ _____- the organism is spread out on the plate to give lawn of growth after incubation. Filter paper soaked in antibiotic solution is placed onto the plate prior to incubation. During incubation the drug will diffuse out and , if it is effective, will give a clear zone of where growth is prevented Kirby Bauer / disk diffusion test ______________- indicated the level of sensitivity or an organism to a drug zone of inhibition gram staining: steps 1-9 1) stain with crystal violet for 1 minute 2) wash off stain with tap water 3) stain with gram's iodine for 1 minute 4) wash off gram's iodine with tap water 5) add 95% alcohol drop by drop until alcohol runs almost clear 6) wash of 95% alcohol with tap water 7) counterstain with safranin for 45 seconds 8) wash off safranin with tap water 9) blot dry with bibulous paper gram staining step 1: stain crystal violet for 1 minute: what does this do? this stains all cells, both G+ and G-, PURPLE gram staining step 5: add 95% alcohol drop by drop until alcohol runs almost clear: what does this do? this process decolorized G- cells. The G+ cells remain purple because the dye cannot leave through the thick layer of peptidoglycan gram staining step 7: counterstain with safranin for 45 seconds: what does this do? this stains the now colorless G- cells PINK _____ ____ uses H2O2 to determine if the bacteria can use oxygen or not. If the test is positive (produces bubbles) the organism is Staphylococci, if the test is negative (no bubbles) the organisms is streptococci catalase test catalase test- positive: __________ and the organism is ___________ produces bubbles and organism is staphylococci catalase test- negative: _________ and the organism is _________ non bubbles and the organism is steptococci ______ ______ _____(____)- key ingredient is sheep blood; tested on bacteria inoculated from a patient's throat swab to test for the presence of streptococci Blood Agar Plate (BAP) ______ _____- the bacteria's hemolytic enzymes completely break the blood cells- the pattern results in the media displaying a clear halos around bacterial colonies (ex. streptococcus pyogenes) beta hemolysis ______ _____- the bacterial enzymes only partially break down the blood cells -the results in the media showing a yellowish/greenish/brownish discoloration (like a bruise) around the colony, indicating incomplete hemolysis (ex. normal flora) alpha hemolysis _____ ____- essentially no hemolysis at all- bacteria have no effect on the red blood cells, and there is no change to the color of the medium (ex. normal flora) gamma hemolysis ________- exhibit color change when a certain kind of microorganisms grows differential _________- allows growth of only certain types of microbes and inhibits growth of other types of microbes selective ________: -BAP -MSA -EMB -MacConkey's differential _______: -MSA -MacConkey's -PEA -EMB selective ________ _______- key ingredients are NaCl and mannitol salt; tested on bacteria inoculated from human skin MSA plate ______ _______ (pathogenic) is mannitol fermenter and turns MSA a bright yellow color staphylococcus aureus _______ ______(normal flora) does not ferment mannitol and the naturally orange-pink color of the agar does not change staphylococcus epidermidis _______ _____- key ingredients are neutral red (pH indicator), lactose (disaccharide), crystal violet, and bile salts MacConkey Agar _________ _____: grows G- bacteria (inhibits growth of G+ bacteria) MacConkey Agar __________ _____: G- lactose-fermenting bacteria turn the plate pink -escherichia -klebsiella -enterobacter -hafina -citrobacter MacConkey Agar _______ ____: selective and differential medium used to isolate fecal coliforms. Eosin Y and methylene blue are pH indicator dyes which combine to form a dark purple precipitate at low pH EMB plate ______ _____: selective medium used to cultivate gram + organisms. Active ingredient: phenylethyl alcohol, which inhibits growth of gram- organisms by interfering with DNA synthesis PEA plate ______ _____ exhibits color change when a certain kind of microorganisms grows on them giving us information about the type of microbe growing there differential media _______ ____ allows growth of only certain types of microbes and inhibits the growth of other types of microbes selective media what is the purpose of high salt in mannitol salt agar? inhibits growth of negative organisms, selective for halophiles, can differentiate pathogenic and non pathogenic staphylococcus what is the purpose of lactose in MacConkey Agar? for fermentation and termination and if it ferments it turns the dye red (pink) what is the purpose of blood in blood agar? blood acts as an enrichment ingredient for cultivation of fastidious organisms, blood also permits demonstrations of hemolytic properties what is the purpose of phenylethyl alcohol agar? inhibits effects of gram- organisms what is the purpose of eosin and methylene blue dyes in eosin-methylene blue agar? allows growth of G- bacteria. It isolated fecal coliforms why is phenol red added to the fermentation tubes? how does it work? phenol red is added as a pH indicator. Phenol red will turn yellow below pH of 6.8 and a dark pink red above a pH of 7.4. Yellow will mean it is acidic, The pink is basic why is it important not to incubate the fermentation tubes beyond 24 hours? if the fermentation tubes are incubated beyond 24 hrs, the acids may be further metabolized and converted back to neutrality or even alkalinity e. coli ferments ______ and ______ lactose and dextrose s epidermidis ferments _______ but not _____ lactose but not dextrose s marcesens ferments _______ but not ______ lactose but not dextrose b subtilis ferments _______ and ________ lactose and dextrose explain why the light microscope is also called the compound microscope: there are several lenses explain why the specimen must be centered in the field of view on low power before going to high power: on high power its harder to find specimen, it is also nearly impossible to find if not centered b/c that means it wouldn't be in the field of view a microscope has a 20X ocular eyepiece and two objectives of 10X and 40X what is the low and high-power magnification: 200X and 860X simple staining: did you air dry your smear before heat fixing it? Why do you think this is important? yes, this is important bc air drying will ensure that all water is dried. It is important to make sure that water is dried bc if you heated the slide while it was wet, the water would change the features of the bacterial cells on the slide which will cause the cells to burst simple staining: how different will your results be if you forget to heat fix your sample before staining it? the bacteria may wash off when you stain and not heat fixing will cause bacteria to stay on the slide simple staining: which dye did you use to stain your sample? is it acidic or basic in nature? Give your reasons for using this dye: used crystal violet to stain my sample which is basic in nature, staining cells makes it easier to observe bacteria bc w/o using the dye it would become difficult to see cells bc they are transparent and the cells are negatively charged differential staining: describe the difference between gram+ and gram- cell walls gram- cell walls contain a thin peptidoglycan layer, it is also surrounded by plasma membrane. Gram+ cells have thick peptidoglycan layer and will stain purple differential staining: what causes gram- bacteria to stain pink? gram- cannot retain the crystal violet because of a thin peptidoglycan layer differential staining: what causes gram+ bacteria to stain purple? gram+ appears purple bc it retains the dye because of the thick peptidoglycan layer differential staining: what is the purpose of iodine in the gram stain's procedure? iodine is used in gram staining because of mordents, which is bc it increases the affinity of the cells for a stain which makes gram- and gram+ purple fomite transmission is _____ indirect ______ ______ spread of infection from one host to another by direct contact, indirect contact or respiratory droplets contact transmission _____ ______ spread of pathogen via air, drinking water, and food, as well as bodily fluids being handles outside the body vehicle transmission _______ animals that transmit diseases from one host to another vectors ______- agar is cooled in a _____ position, these are useful for maintaining pure cultures slants, cooled in a slanted position _______ plate grows gram pos bacteria, and mimics the resp. system PEA PEA plate is diff/selective; dye used is _____ and _____ Selective; eosin y and methylene blue what is the active ingredients in MSA plates? mannitol and salt MSA plate grows gram ________ bacteria positive MSA plate mimics what body system? skin (integumentary) blood agar plate active ingredient 5% sheep blood what body system does BAP (blood agar plate) mimic? respiratory what reaction occurred with pyogenes on BAP beta hemolysis what reaction occurred with on BAP gamma hemolysis what reaction occured with s. aureus on BAP alpha hemplysis MacConkey Agar active ingredients bile salts, crystal voilet MacConkey Agar mimics what body system? GI system __________________ plates grow gram negative bacteria only MacConkey acid fast staining EMB plate is _______________________ selective and differential deep agar flagellar stain agar broth agar slant fermintation: PRB tubes (phenyl red indicator) EMB Plate On a MSA plate, what does yellow and red reaction mean? yellow= acid/ fermentation red= no acid/ ferment