ch6-9

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1

Assume you inoculated 100 facultatively anaerobic cells onto nutrient agar and incubated the plate aerobically. You then inoculated 100 cells of the same species onto nutrient agar and incubated the second plate anaerobically. After incubation for 24 hours, you should have

  1. more colonies on the aerobic plate.
  2. more colonies on the anaerobic plate.
  3. the same number of colonies on both plates.

the same number of colonies on both plates.

2

The term trace elements refers to

  1. the elements CHONPS.
  2. vitamins.
  3. nitrogen, phosphorus, and sulfur.
  4. small mineral requirements.
  5. toxic substances.

small mineral requirements.

3

Which one of the following temperatures would most likely kill a mesophile?

  1. -50°C
  2. 0°C
  3. 9°C
  4. 37°C
  5. 60°C

60

4

Which of the following is not a characteristic of biofilms?

  1. antibiotic resistance
  2. hydrogel
  3. iron deficiency
  4. quorum sensing

iron deficiency

5

Which of the following types of media would not be used to culture aerobes?

  1. selective media
  2. reducing media
  3. enrichment media
  4. differential media
  5. complex media

reducing media

6

An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an

  1. aerobe.
  2. aerotolerant anaerobe.
  3. obligate anaerobe.

aerotolerant anaerobe.

7

Which of the lines best depicts the log phase of Listeria monocytogenes growing in a human?

A

8

Which of the lines best depicts the log phase of a thermophile incubated at room temperature?

c

9

Medium 2 is

  1. selective.
  2. differential.
  3. both selective and differential.

selective

10

Medium 1 is

  1. selective.
  2. differential.
  3. both selective and differential.

selective and differential

11

Which of the following does not kill endospores?

  1. autoclaving
  2. incineration
  3. hot-air sterilization
  4. pasteurization
  5. All of the above kill endospores.
  1. pasteurization
12

Which of the following is most effective for sterilizing mattresses and plastic Petri dishes?

  1. chlorine
  2. ethylene oxide
  3. glutaraldehyde
  4. autoclaving
  5. nonionizing radiation

ethylene oxide

13

Which of these disinfectants does not act by disrupting the plasma membrane?

  1. phenolics
  2. phenol
  3. quats
  4. halogens
  5. biguanides

halogens

14

Which of the following cannot be used to sterilize a heat-labile solution stored in a plastic container?

  1. gamma radiation
  2. ethylene oxide
  3. supercritical fluids
  4. autoclaving
  5. short-wavelength radiation

autoclaving

15

Which of the following is used to control microbial growth in foods?

  1. organic acids
  2. alcohols
  3. aldehydes
  4. heavy metals
  5. all of the above

organic acids

16
  1. Which disinfectant is the most effective?

A

17

Which disinfectant(s) is (are) bactericidal?

  1. A, B, C, and D
  2. A, C, and D
  3. A only
  4. B only
  5. none of the above

A, C, and D

18

Which of the following is not a characteristic of quaternary ammonium compounds?

  1. bactericidal against gram-positive bacteria
  2. sporicidal
  3. amebicidal
  4. fungicidal
  5. kills enveloped viruses
  1. sporicidal
19

A classmate is trying to determine how a disinfectant might kill cells. You observed that when he spilled the disinfectant in your reduced litmus milk, the litmus turned blue again. You suggest to your classmate that

  1. the disinfectant might inhibit cell wall synthesis.
  2. the disinfectant might oxidize molecules.
  3. the disinfectant might inhibit protein synthesis.
  4. the disinfectant might denature proteins.
  5. he take his work away from yours.
  1. the disinfectant might oxidize molecules.
20

Which of the following is most likely to be bactericidal

  1. membrane filtration
  2. ionizing radiation
  3. lyophilization (freeze-drying)
  4. deep-freezing
  5. all of the above

ionizing radiation

21

Transfer of DNA from a donor to a recipient cell by a bacteriophage.

  1. conjugation
  2. transcription
  3. transduction
  4. transformation
  5. translation

transduction

22

Transfer of DNA from a donor to a recipient as naked DNA in solution.

  1. conjugation
  2. transcription
  3. transduction
  4. transformation
  5. translation

transformation

23

Feedback inhibition differs from repression because feedback inhibition

  1. is less precise.
  2. is slower acting.
  3. stops the action of preexisting enzymes.
  4. stops the synthesis of new enzymes.
  5. all of the above

stops the action of preexisting enzymes.

24

Bacteria can acquire antibiotic resistance by all of the following except

  1. mutation.
  2. insertion of transposons.
  3. conjugation.
  4. snRNPs.
  5. transformation.

snRNPs.

25

Suppose you inoculate three flasks of minimal salts broth with E. coli. Flask A contains glucose. Flask B contains glucose and lactose. Flask C contains lactose. After a few hours of incubation, you test the flasks for the presence of β-galactosidase. Which flask(s) do you predict will have this enzyme?

  1. A
  2. B
  3. C
  4. A and B
  5. B and C

c

26

Plasmids differ from transposons in that plasmids

  1. become inserted into chromosomes.
  2. are self-replicated outside the chromosome.
  3. move from chromosome to chromosome.
  4. carry genes for antibiotic resistance.
  5. none of the above

are self-replicated outside the chromosome.

27

Mechanism by which the presence of glucose inhibits the lac operon.

  1. catabolite repression
  2. DNA polymerase
  3. induction
  4. repression
  5. translation

catabolite repression

28

The mechanism by which lactose controls the lac operon.

  1. catabolite repression
  2. DNA polymerase
  3. induction
  4. repression
  5. translation

induction

29

Two offspring cells are most likely to inherit which one of the following from the parent cell?

  1. a change in a nucleotide in mRNA
  2. a change in a nucleotide in tRNA
  3. a change in a nucleotide in rRNA
  4. a change in a nucleotide in DNA
  5. a change in a protein

a change in a nucleotide in DNA

30

Which of the following is not a method of horizontal gene transfer?

  1. binary fission
  2. conjugation
  3. integration of a transposon
  4. transduction
  5. transformation

binary fission

31

Restriction enzymes were first discovered with the observation that

  1. DNA is restricted to the nucleus.
  2. phage DNA is destroyed in a host cell.
  3. foreign DNA is kept out of a cell.
  4. foreign DNA is restricted to the cytoplasm.
  5. all of the above

phage DNA is destroyed in a host cell.

32
  1. The DNA probe, 3’-GGCTTA, will hybridize with which of the following?
    1. 5’-CCGUUA
    2. 5’-CCGAAT
    3. 5’-GGCTTA
    4. 3’-CCGAAT
    5. 3’-GGCAAU
  1. 5’-CCGAAT
33

Which of the following is the fourth basic step to genetically modify a cell?

  1. transformation
  2. ligation
  3. plasmid cleavage
  4. restriction-enzyme digestion of gene
  5. isolation of gene

ligation

34

The following enzymes are used to make cDNA. What is the second enzyme used to make cDNA?

  1. reverse transcriptase
  2. ribozyme
  3. RNA polymerase
  4. DNA polymerase

ribozyme

35

if you put a gene in a virus, the next step in genetic modification would be

  1. insertion of a plasmid.
  2. transformation.
  3. transduction.
  4. PCR.
  5. Southern blotting.

transduction.

36

You have a small gene that you want replicated by PCR. You add radioactively labeled nucleotides to the PCR thermal cycler. After three replication cycles, what percentage of the DNA single strands are radioactively labeled?

  1. 0%
  2. 12.5%
  3. 50%
  4. 87.5%
  5. 100%

87.5%

37

Pieces of human DNA stored in yeast cells.

  1. antisense
  2. clone
  3. library
  4. Southern blot
  5. vector

library

38

A population of cells carrying a desired plasmid.

  1. antisense
  2. clone
  3. library
  4. Southern blot
  5. vector

clone

39

Self-replicating DNA for transmitting a gene from one organism to another.

  1. antisense
  2. clone
  3. library
  4. Southern blot
  5. vector

vector

40

DNA that hybridizes with mRNA.

  1. antisense
  2. clone
  3. library
  4. Southern blot
  5. vector

antisense