APB 2170 INTRODUCTORY MICROBIOLOGY

SUMMER 1993



MULTIPLE CHOICE: There are 25 questions each worth 4 points for a total of 100 points. There is only one answer per question. Use a #2 pencil to completely circle your answers on the Scantron sheet. Fill in your Last Name First and also fill in your SS#.
 
 
  1. In order to make a 1 x 10-6 dilution of a bacterial sample, what would the input volume to diluent volume be, if the final volume of each dilution were to be 10 ml?
  1. 0.1/9.9; 0.1/9.9; 1/9; 1/9
  2. 1/9; 1/9; 1/9; 1/9
  3. 0.1/9.9; 0.1/9.9; 0.1/9.9; 1/9
  4. 1/9; 1/9; 1/9; 0.1/9.9
  1. Suppose you plated out 0.25 ml from a 1 x 10-6 dilution tube onto a nutrient agar plate. After spreading and leaving the plate at 370C overnight, 125 colonies were seen on the plate the next day. What would be the bacterial cell/ml count of your culture?

    2.  

     
     

    a) 5 x 107 b) 2.5 x 107 c) 5 x 108 d) 6 x 106
     
     

  2. Using a Petroff-Hausser counter, you counted 10 squares with a total of 1000 bacterial cells. What is the concentration of the number of bacterial cells/ml, if each square was 1/1,250,000 ml?

    3.  

     
     

    a) 1.25 x 108 b) 1.25 x 107 c) 5 x 108 d) 2.5 x 108
     
     

  3. If the bacterial cell count during the log phase of a bacterial growth curve was 2 x 188 cells /ml, what would be the cell count /ml after 3 more generations?

    4.  

     
     

    a) 1.6 x 105 b) 2 x 105 c) 1.6 x 107 d) 1.6 x 107
     
     

  4. During the lag phase of a bacterial growth curve
  1. the bacteria are actively dividing, such that there is an exponential rate of growth occurring
  2. no cell division is taking place but the cell is actively synthesizing enzymes needed for DNA replication
  3. toxins in high concentrations are now present in the medium
  4. there are just as many cells dying as there are cells that are being propagated by cell division

 
 
 
 
 
 
  1. Sterilization
  1. is a process which destroys vegetative or growing cells but not there spores
  2. can be achieved by use of ethylene oxide
  3. is achieved by using steam heat at 750C for 10 minutes
  4. of milk can be achieved by the pasteurization method
  1. An antiseptic
  1. by definition, is a chemical that controls the growth of microbes on living tissue
  2. by definition, is a chemical that is used to control the growth of microbes on inanimate objects
  3. is a chemical such as 70% alcohol
  4. is a chemical that sterilizes objects
  1. An organic acid derivative such as
  1. Cepecol is used as a mouth wash
  2. Such as pHisoHex is used as a mold inhibitor in bakery products
  3. Such as glutaraldehyde is an excellent antimicrobial agent which is put in processed meat products
  4. Such as calcium propionate is used as an antifungal agent in bakery products
  1. H2O2
  1. is not very effective as an antiseptic on surface wounds
  2. is not very effective as an antiseptic in deep wounds
  3. is broken down by the enzyme superoxide dismutase to H2O and O2
  4. is an example of a chemical disinfectant
  1. A chemical that is
  1. less effective than phenol in killing the test bacteria is given a phenol coefficient that is greater than 1
  2. effective as phenol when it is diluted one-half as much as phenol is given a phenol coefficient of 0.5
  3. effective as phenol when it is diluted twice as much as phenol is given a phenol coefficient of 0.5
  4. effective as phenol when it is diluted 4 times as much as phenol is given a phenol coefficient of 0.25

 
 
 
 
 
 
 
 
 
 
  1. One of the physical means of controlling the presence of viable bacteria is
  1. to have HEPA filters with pore sizes greater than 10 um
  2. to autoclave samples at 500F at 10 psi for 10 minutes
  3. to use 70% ethanol as a swab on inanimate objects
  4. to refrigerate foods thereby preventing the growth of human pathogens
  1. Which of the following is the correct answer?
  1. Ionizing radiation uses long wave lengths to penetrate objects and thereby sterilizes them
  2. Ultraviolet light helps control bacterial growth by causing mutations in their DNA thereby affecting their growth
  3. Gamma rays have long wave lengths
  4. U.V. light has deep penetrating power
  1. The phenol coefficient test is carried out using
  1. Staphylococcus aureus, Salmonella typhi and Pseudomonas aeruginosa as the test organisms
  2. physical agents that inhibit the growth of test microorganisms
  3. Staphylococcus aureus, Escherichia coli and Neisseria gonorrhoeae
  4. Streptococcus pyogenes, Mycobacterium tuberculosis and Treponema pallidum
  1. Pseudomonas aeruginosa is a
  1. gram-positive aerobe
  2. gram-positive spore forming rod
  3. gram-positive aerobic rod
  4. is a fussy bacterium that requires special medium for its growth in culture
  1. The bacterium that
  1. changes ethanol to acetic acid is in the genus Acetobacter
  2. causes syphilis is Neisseria gonorrhoeae
  3. causes NGU is Neisseria gonorrhoeae
  4. abortion in cattle is Streptococcus mutans
  1. A member of the gram-negative facultatively anaerobic rod shaped bacterial group is
  1. Streptococcus pyogenes
  2. Clostridium tetani
  3. Hemophilus influenzae
  4. Treponema pallidum
  1. Salmonella typhi
  1. is the agent responsible for outbreaks of salmonellosis
  2. is the agent that causes shigellosis
  3. is a gram-positive aerobe
  4. can be disseminated in the population by fecal contamination of foods and water by carriers who are immune to their infection
  1. Members of the genus Chlamydia
  1. are spread by vectors such as ticks and fleas
  2. have an effective electron transport system that generates ATP
  3. may cause NGU which may lead to sterility of both males and females
  4. are found as the normal flora in the genital tract of women especially during the pre-pubescent period
  1. Bacterium such as
  1. Neisseria gonorrhoeae is round-shaped and gram-negative
  2. Streptococcus pneumoniae is not an important disease causing agent
  3. Lactobacillus cremora is irregularly shaped, gram-negative and a spore former
  4. Streptococcus mutans converts glucose to lactic acid and fructose to ethanol
  1. Staphylococcus aureus
  1. forms colonies on agar plates that have a metallic green sheen
  2. cannot survive on their own away from the body for a prolonged period of time
  3. forms chains of round shaped cells
  4. is a very versatile bacterium in that it can grow in environments which are unsuitable for most human pathogens
  1. The microorganism
  1. that synthesizes tetracycline is Streptomyces griseus
  2. that synthesizes aureomycin is Streptomyces aureofaciens
  3. that synthesizes tetracycline is a fungus
  4. that synthesizes penicillin is Streptomyces penicillium
  1. A saprophyte by definition
  1. is an organism that can live in solutions of high osmotic pressure
  2. is a chemoheterotroph
  3. can only be unicellular
  4. is an organism that grows in an acid environment

 
 
  1. The fungus that
  1. forms a sporangium is in the phylum Zygomycota
  2. forms a sporangium is in the phylum Ascomycota
  3. forms basidiospores is in the phylum Ascomycota
  4. forms an ascus is in the phylum Deuteromycota
  1. Mushrooms
  1. are unicellular
  2. are procaryotes
  3. are in the phylum Ascomycota
  4. produce basidiospores
  1. Candida albicans
  1. is the name of a plant that blooms around Easter time
  2. is easily controlled by antibiotics such as tetracycline
  3. can survive in an acid environment
  4. is a gram-positive, strictly anaerobic spore forming fungus