Principles of Microbiology Lab Exam 1 Practice Questions And Answers Well Elaborated.

TSA - correct answers Tryptic Soy Agar -general bacterial medium BHI - correct answers Brain-Heart Infusion -general bacterial medium PDA - correct answers Potato Dextrose Agar -general fungal medium Microorganisms are - correct answers ubiquitous -most successful life form on earth Importance of Microbes - correct answers-cause disease in plants and animals -be used to produce antibiotics and other pharmaceuticals -used to produce a wide range of food products -used in industry -nutrient cycling Which plates are incubated upside down vs. right-side up? - correct answersTSA are upside down to prevent condensation accumulation on the lid from dripping and scattering colonies. PDA plates are right side up due to being incubated at a lower temperature and not creating condensation Parfocal - correct answersobject in focus while changing objective lenses Field of View - correct answersarea that you can see the object Total Magnification - correct answersobjective x ocular Resolution - correct answersdistance between two objects Contrast - correct answerslight difference between objects Ocular eyepieces - correct answerssystem of lenses that usually magnify the primary image 10x Thumbwheel - correct answersadjustment to accommodate the distance between the observer's eyes Revolving nosepiece - correct answersplatform that can be rotated to switch from one objective to another Objectives - correct answersusually 3 magnifications 10x 40x 100x Slide holder - correct answersspring-loaded holder that keeps the microscope slide firmly in place on the stage Diaphragm lever - correct answersopens and closes the condenser diaphragm to control the amount of light striking the specimen Condenser - correct answerscondenses light rays into a cone, thereby controlling the intensity of illumination Mechanical stage and stage controls - correct answersallows the slide to be moved in a horizontal plane Light intensity control - correct answersturns the light source on and off and controls the intensity Adjustment knobs - correct answersmoves the stage up and down in order to focus on a specimen Eukaryotes - correct answersfungi protozoans What is the most important instrument in the history of microbiology? - correct answersthe light microscope wet mount - correct answersa liquid suspension of living microorganisms prepared on a microscope slide and viewed under the light microscope smear prep - correct answerswhere you smear bacteria onto a slide and fix the bacteria so they will not wash off during staining procedures A ________ __________ is the simplest way to see whether or not the microorganisms are motile. - correct answerswet mount -determines undistorted shapes and sizes of individual cells Disadvantage to Wet Mount - correct answerswet mounts dry out quickly -takes about 10 minutes Hay infusion - correct answersprovides an excellent mixed culture of many different types of microorganisms -hay or grass into a large beaker with lake water and incubating it at room temp. -after one day add 2 mL of Luria Broth to promote growth of organisms How long should a loop be left in the incinerator? - correct answers10 seconds, no less and no more Aseptic Technique - correct answersusing practices and procedures to prevent contamination from pathogens Pure Culture - correct answersan isolation of one bacteria narrowed down to where one colony can be seen -one organism growing Streak Plate - correct answerspetri plate used to separate the bacteria in a mixed culture so that individual cells can be isolated from it If you touch bacterial culture with a hot loop: - correct answersyou will kill and aerosolize the bacteria Colony - correct answerscontains only descendants of a single, sexually-reproducing cell, all cells are identical. 3 Types of Growth Patterns - correct answers1. isolated colony on the surface of a nutrient agar plate 2. nutrient broth culture 3. agar slant 3 Types of Growth Characteristics - correct answers1. colony shape 2. margin of the colony 3. elevation of the colony Thioglycolate Tube - correct answersdesigned to meet oxygen requirements of different organisms Cultural Characteristics - correct answersshape color characteristics that can help identify the organism Cellular Characteristics - correct answerscell shape gram nature etc Isolated Colony on Nutrient Agar Plate - correct answersisolates pure culture Nutrient Broth Culture - correct answersused for propogation Agar Slant - correct answersused for short term storage Thioglycolate - correct answers Strict/Obligate Aerobe - correct answerswill only grown in the presence of oxygen -towards top of tube Strict/Obligate Anaerobe - correct answerswill only grow in the absence of oxygen -towards bottom of the tube Facultative Anaerobe - correct answerswill growth in both the presence and absence of oxygen -throughout tube but more toward top due to ATP generation Aerotolerant Anaerobe - correct answersdo not utilize oxygen but can survive and grow in its presence Microaerophile - correct answersit needs oxygen, but can only tolerate low concentrations of it. -right under the surface of the top Bacterial Shapes - correct answerscoccus bacillus spiral Coccus - correct answersround Bacillus - correct answersrod shaped Spiral forms - correct answersspirochetes spirilla Disadvantages to Fixation - correct answersoften distorts the cell's appearance and therefore motility can no longer be studied Advantages of Fixation - correct answershelps with adherence to the slide assures cells won't be washed off during staining Purpose of Smear Prep - correct answersbefore bacteria can be stained, it must be prepped and fixed to a slide allows bacteria to be viewed Four Kinds of Stains - correct answers1. Gram 2. Capsule 3. Endospore 4. Acid-Fast What would happen during a smear prep process, if you didn't let the slide completely dry? - correct answersThe cells will explode Christian Gram - correct answers1884 developed the Gram stain Gram Stain - correct answersdetermines the difference between gram (+) and gram (-) cells based on the structure of their cell walls Crystal Violet - correct answersprimary stain in gram stain cationic dye (basic) Safranin - correct answerscounterstain in gram stain -taken up by gram (-) cells Mordant - correct answersiodine in gram stain -combines with dye to fix it to the material Crystal-Violet Iodine Complex - correct answersInsoluble precipitate created after mordant is added in gram stain Decolorizer - correct answerstype of alcohol -washes primary stain out of gram (-) cells Steps in Gram Stain - correct answers1. Primary: Crystal Violet 2. Mordant: Iodine 3. Decolorizer: Alcohol 4. Counterstain: Safranin Gram (+) cells should appear: - correct answers bluish-purple Gram (-) cells should appear: - correct answers redish-pink Gram Positive - correct answers thick cell wall of peptidoglycan glycosaminoglycan chains interlinked with short peptides