medical microbiology lab exam questions with correct detailed answers guaranteed success.

aseptic technique - correct answers the method of handling microbes and materials in a way that minimizes contamination inoculation - correct answers process of transferring a microbe from one medium to the next inoculum - correct answers sample being transferred inoculating loop and inoculating needle - correct answers two instruments used to transfer an inoculum isolation streak plate - correct answers widely used method to separate individual bacteria from mixtures colony - correct answers arises from a single bacterium that divides repeatedly over time to form a mass of millions of cells fungal body - correct answers visible collection of hyphae simple stain - correct answers uses only one type of stain to complete procedure useful for observing morphology or shape and the arrangement of cells direct stains - correct answers procedures that stain cells bascillus (oblong, rod) coccus (sphere) spirillum (comma-shaped) - correct answers three most common shapes of bacteria diplo- - correct answers describes the arrangement where two cells remain attached after fission strepto- - correct answers arrangement of long chains of cells staphylo- - correct answers grapelike clusters of cells smear - correct answers thin film of bacteria applied to a slide acidic chromogen - correct answersnegatively charged chromophore used in dyes of negative staining this caused dye to be repelled by bacteria cells (cell remains uncolored and background is stained) capsule - correct answersglycocalyx that is compact and firmly attached to the cell wall composed of polypeptides and or polysaccharides can serve as water and energy reserve, as a means to evade the host's immune system (evade phagocytosis), and as an anchor or surface attachment meachanism slime layer - correct answersglycocalyx that is less compact and loosely attached to the cell wall glycocalyx - correct answersan extracellular structure that literally means "sugar cover" differential stain - correct answersdifferentiates by color two major groups of bacteria ex: gram stain gram stain - correct answersa differential stain that differentiates gram-negative and gram-positive bacteria by color cells response to this type of stain is based on the composition of the cell wall involves a use of a dye stain, mordant, and a decolorizer gram positive cell wall - correct answersmade up of very thick layer of peptidoglycan gram negative cell wall - correct answersconsist of very thin layer of peptidoglycan surrounded by an outer membrane containing lipopolysaccharides crystal violet - correct answersprimary stain in gram stain is a basic stain and stains all cells on slide gram iodine - correct answersmordant for gram stain mordant - correct answersfix color into the cell or intensify color safararin - correct answerscounter stain in gram stain acid-fast cells - correct answershave a waxy cell wall and mycolic acid located in the cell wall makes these cells resistant to desiccation and disinfectants also makes it difficult to stain these cells using traditional staining methods Ziehl-Neelsen Kinyoun - correct answerstwo methods used to stain acid fast bacteria endospore - correct answerssurvival structure formed within the bacterial cell wall that allows the cell to survive until environmental conditions improve contains copy of the organism's chromosome, a little cytoplasm, and a small amount of cell machinery sporulation - correct answersstarts with process of replication of bacterial chromosomes and the spatial separation of the chromosomes in different regions within the cell's cytoplasm separation can occur through the formation of septum or wall within the cell forespore - correct answerswill eventually mature to become the endospore sporangium - correct answersmetabolically active and produces and deposits the compounds necessary for the completion of the spore coat layers terminal endospore - correct answersendospore that develops at the end of a cell central endospore - correct answersendospore that forms in the middle of the cell subterminal endospore - correct answersendospore that is located between the center and the end of the cell endospore stain - correct answersdifferential stain that differentiates bacteria who have an endospore and those that do not malachite green - correct answersprimary stain for endospore stain safranin - correct answerssecondary stain for endospore stain formation of endospore - correct answers Brownian movement - correct answerstypically caused when water molecules collide with the cells and make them move cells get bounced around like a pinball and oscillate and appear to shake in place this is not real motility blood agar - correct answersmedia that is both enriched and differential this allows many bacteria to grow on this medium some bacteria simply grow on media others partially and completely break down media ability for some bacteria to break down medium makes it differential hemolysins - correct answerstoxins made by Streptococcus and Staphylococcus that breaks down red blood cells alpha-hemolysis - correct answerscauses partial lysis of RBCs which leads to darkening of the blood agar around the colony Hemoglobins breakdown causing the green color often seen beta-hemolysis - correct answerscause complete lysis of the RBCs and breakdown of hemoglobin which leads to colorless clearing of the blood afar around the colony gamma-hemolysis - correct answerscauses no hemolysis mannitol salt agar - correct answersmedia that is both selective and differential contains high concentrations of salt which makes the medium selective by inhibiting the growth of most bacteria but allowing halophiles (salt tolerant) to grow contains sugar (mannitol) and pH indicator phenol red disease causing bacteria ferment the sugar and release acid into the medium which turns the phenol red in the medium and around the colony to turn yellow non-disease causing staphylococci grow but do not change the medium's color the combination of mannitol and phenol red allows for differentiation between pathogenic and nonpathogenic staphylococci fecal coliforms - correct answers used as indicators of the presence of other harmful microorganisms that pose significant threat to humans higher levels means that there is a greater risk that something harmful will also be there eosin methylene blue (EMB) agar - correct answersone confirmatory step used to look for presence of intestinal bacteria in water medium that is both selective and differential