Microbiology Lab Exam

Microbiology MULTIPLE CHOICE. Choose the one alternative that best complete the statement or answers the question. Know the parts of the microscope Know the microscope parts with their functions. What is the total magnification of a specimen using the 40X objective lens? a.) 40X b.) 10X c.) 400X d.) 4000X Identify the shape of this bacteria. a.)Coccus b.)Bacillus c.) Spirillum d.) None of the above All bacteria are prokaryotic. True 70866020002500Identify the shape of the bacteria in this image. a.) Bacillus b.) Coccus c.) Spirillum d.) None of the above Identify the name of this figure. a.) Coccus b.) Bacillus c.) Spirillum d.) None of the above Bacterial cells are as large as yeast cells. False Genetic material of bacteria and yeast cells is enclosed inside a nucleus. False Label the bacterial cell model to review prokaryotic cell parts Identify the shape of bacterial cells in this picture: 633046-2872300 a.) bacillus b.) coccus c.) spirillum Identify the shape of bacterial cells in this picture: a.) bacillus b.) coccus c.) spirillum Identify the shape of bacterial cells in this picture: a.) bacillus b.) coccus c.) spirillum If a bacterial cluster appears as a square of four cocci, this arrangement is called as a.)Diplococcus b.) Tetrad c.) Staphylococcus d.) Sarcinae e.) Streptococcus A streptococcus arrangement shows a.) Cocci in chains b.) Cocci in irregular clusters c.) Cocci in pairs d.) Cocci in cubes of 8 e.) A single coccus The arrangement inside the box is depicting a streptococcus arrangement. True False Streptococcus: A chain of round bacteria Staphylococcus: Irregular group of round bacteria with no specific arrangement. Sarcinae: Group of cocci arranged in cluster of 8 Diplobacillus: Two rod shaped bacteria attached together Study of cell shape and arrangement is called as morphology. True The proper procedure for smear preparation is: a. Air dry-->heat fix-->make smear  b. Make smear-->air dry-->heat fix  c. Make smear-->heat fix-->air dry  d. Heat fix-->air dry-->make smear What type of staining does this figure show? a.) Simple staining b.) Differential staining c.) Positive staining d.) Negative staining e.) Acid fast staining In staining procedure used to identify Mycobacterium smegmatis, the decolorizer used is_______. a.) 90% ethyl alcohol b.) Acid alcohol c.) Iodine d.) Safranin These bacteria are stained with acid-fast staining. Figure 1 Figure 2 Figure 1 shows____and Figure 2 shows_____bacteria. a.) Non-acid fast; acid fast b.) Acid fast; non-acid fast c.) Pathogenic; non-pathogenic d.) Positive; negative e.) Hemolytic; non-hemolytic 1. At the end of Gram staining, Gram positive bacteria stain purple while Gram negative bacteria stain red. True What is the purpose of using decolorizing agent in Gram staining? a.) In Gram negative cells alcohol increases the porosity of cell wall by dissolving the lipid in outer layer, removing the CV-I complexes b.) In Gram positive cells alcohol dehydrates cell wall and shrinks the pores, making it difficult to remove CV-I complexes. c.) To dissolve peptidoglycan in Gram positive cell wall d.) To dissolve peptidoglycan in gram negative cell wall e.) Both a and b are correct 1. Why are bacteria not stained in negative staining? a.) Both the bacterial cell wall and the dye are negatively charged, so they repel each other b.) Both the bacterial cell wall and the dye are positively charged, so they repel each other c.) Cell wall is too thick to allow the dye molecules to penetrate d.) Outer lipid layer prevents the dye molecules to bind with the cell wall e.) None of the above Know parts of Capsule What structure is the pointer pointing at? a.) Capsule b.) Slime layer c.) Flagella d.) Central endospore e.) Terminal endospore Know parts of the Endospores What type of flagellar arrangement is seen in these bacteria? (hint:looks like wheat and grain) a.) Monotrichous b.) Amphitrichous c.) Peritrichous d.) Lophotrichous Amphitrichous flagellar arrangement show presence of a cluster of flagella at one end only. False All bacteria have flagella. False Presence of flagella contributes to bacterial pathogenecity. True Which of the following tube(s) shows bacterial motility? a.) Tube 1 (thicker lining of blood down middle) b.) Tube 2 c.) Both d.) None What is the concentration of agar in the motility test media? a.) 1%-5% b.) 5%-10% c.) 0.1%-0.5% d.) 0.3%-0.5% e.) Doesn’t have agar in it Know the terms about flagella and motility Tritetrazolium chloride--Turns red in reduced form 0.3%-0.5%--Concentration of agar Hanging drop technique--Depression slide Non motile bacteria --Brownian movement How many different types of bacteria were mixed in this experiment? a.) One b.) Two c.) Three d.) Four e.) Countless What is the name of the technique used to set up this dish for isolation of pure culture? a.) Pour plate method b.) Dilution method c.) Streak plate method d.) Standard plate count e.) None of the above What are the criteria used in identification of different types of colonies? a.) Distance between each colony b.) Found on surface of media only c.) Found inside the media only d.) Color, elevation, texture and margins e.) All of the above Looking at the colony number and distribution, which plate should be used for isolation of pure culture? Dilution 1 Dilution 2 Dilution 3 Dilution 4 a.) Dilution 1 b.) Dilution 2 c.) Dilution 3 (larger round specks) d.) Dilution 4 (one very large speck) e.) Both 3 and 4 In pour plate method, what will be expected result, if the plates were incubated for an extended period of time, say 15 days? a.) More colonies will continue to grow b.) Each colony will get bigger until they run out of space and nutrient c.) There will be no change in number and size of colonies d.) All of the above In streak plate method all quadrants get the same number of bacteria. False In an isolated colony obtained from streak plate or pour plate method. a.) All cells are an aggregate of different types of bacteria. b.) All cells are descendants of the same bacteria. c.) Majority belongs to same type of bacteria d.) Both b and c are correct What type of media is MacConkey media? a.) Selective and differential b.) Selective c.) Differential d.) Enriched and differential MacConkey media promotes growth of Gram negative bacteria while inhibiting that of Gram positive bacteria. True If a bacteria grows in MacConkey media and forms red colonies, it means that the bacteria is: a.) G+ and lactose fermenter b.) G- and lactose fermenter c.) G+ and mannitol fermenter d.) G+ and lactose nonfermenter e.) Faculative anaerobes If the growth of a bacteria is inhibited in Mannitol Salt Agar media, it means that the bacteria is a.) Salt tolerant b.) Salt intolerant c.) Mannitol fermenter d.) Strict anaerobe Purpose of having sheep blood in Blood agar media is to a.) Promote the growth of G+ bacteria b.) Promote growth of G-bacteria c.) Detect hemolysis d.) Detect hemolysis and provide nutrients for growth of fastidious bacteria e.) Give media red color This dish contains sheep blood agar media, and three different types of bacteria were inoculated. What type of hemolysis do you observe around the growth on the bottom left of the dish? a.) Alpha hemolysis b.) Beta hemolysis c.) Gamma hemolysis d.) No evidence of hemolysis e.) Mixed hemolysis Recognize parts in an agar 876304953000 Recognize Growth or No Growth 3981454318000 What are the two criteria used to determine if the bacteria fermented a specific carbohydrate? a.) Presence of acid and base b.)Presence of acid and gas c.)presence of black precipitate d.)presence of red and green color e.) Color of media and odor What is the name of pH indicator used in carbohydrate fermentation media? a.) phenol red b.) neutral red c.)bromthymol blue d.) Bromcresol purple e.) citrate Durham tube is placed right side up in purple broth. False Some bacteria produce both acid and gas as a bi-product of carbohydrate fermentation. True All bacteria can ferment sugars. False Where will the strict anaerobe grow in Thioglycollate media? a.) At the top b.) At the bottom c.) All over d.) Slightly below the top e.) Slightly above the bottom The purpose of having Sodium Thioglycollate in the reduced media is to trap the oxygen in the media to facilitate growth of aerobic bacteria. False Know Gas Requirements definitions Faculative anaerobes-¤-Can grow with or without oxygen Aerotolerants -¤-Does not use oxygen for its metabolism, and is not harmed by its presence Thioglycollate-¤-Reacts with free oxygen in the media and removes it Strict anaerobes-¤-Requires with free environment to grow; if exposed to oxygen, it gets killed Capnophiles-¤-Requires high concentration (3-10%) of carbon dioxide for growth 54434119758300To which bacteria was this bacteriophage susceptible? a.) E. aerogenes b.) E. coli c.) E. coli B d.) Both b and c e.) None of the above In this dish, the clear circular area in the upper half of the plate is a plaque. True 5327658191500 Plaque formation on bacterial lawn indicates that a.)The bacteriophage is specific to the host. b.) Bacteriophage is growing outside of the host cell. c.) Bacteria has plasmolysed d.) Bacteria has absorbed water e.) Bacteria is dividing rapidly Phage typing is important to discover the source of specific bacterial infection. True Plaque formation indicates that a.) the bacteriophage is undergoing lysogenic cycle b.) the bacteriophage is undergoing lytic cycle c.) bacteriophage is in latent phase d.) the bacteria in use is not the right host e.) all of the above Match Bacteriophages 33410718478500 In Kirby Bauer Test the antibiotic discs were placed a.) Directly on the media b.) Over the lawn of a bacteria c.) Underneath the lawn of bacteria d.) None of the above What is the clear area around the antibiotic discs called? 6975233653700 a.) Plaque b.) Clear circle c.) Zone of inhibition d.) Zone of antibiotic effectiveness e.) Both c and d Larger the zone of inhibition, less effective is the antibiotic. False Which antibiotic is most effective for this bacteria? 3925281001300 a.) Penicillin b.) Streptomycin c.) Tetracyclin d.) Chloremphenol Which antibiotic is least effective for this bacteria? 2104783785500 a.) Penicillin b.) Streptomycin c.) Tetracyclin d.) Chloremphenicol Which of the following unit is used to measure the zone of inhibition? a.) Inch b.) Centimeter c.) Millimeter d.) Micrometer e.) Meter An antibiotic that is effective against a wide variety of microorganism is called a.) Synthetic b.) Semisynthetic c.) Narrow spectrum d.) Broad spectrum e.) Both c and d Know Staining dyes. Match the items. Use of two dyes Use of a single stain Basic stains with a positively charged chromatogen Negatively charged chromatogens Differential staining 1.) Methylene blue and Crystal violet c. 2.) Simple staining b 3.) Decolorizing agent e 4.) Acidic stains d 5.) Differential staining a