ch6-9 Flashcards

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 term trace elements refers to

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

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

Which of the following is not a characteristic of biofilms?

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

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

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

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

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

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

Medium 2 is

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

Medium 1 is

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

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.

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

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

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

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

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

1. Which disinfectant is the most effective?

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

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

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.

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

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

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

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

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

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

Bacteria can acquire antibiotic resistance by all of the following except

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

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

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

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

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

The mechanism by which lactose controls the lac operon.

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

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

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

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

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

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

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

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.

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%

Pieces of human DNA stored in yeast cells.

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

A population of cells carrying a desired plasmid.

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

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

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

DNA that hybridizes with mRNA.

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