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Microbiology > Practice Exam 2 Questions > Flashcards

Practice Exam 2 Questions Flashcards

1
Q

Who first noticed the possible therapeutic properties of penicillin?

A

Alexander Fleming

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2
Q

Which of the following is the best definition of generation time?

A

The length of time is takes for a population of cells to double

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3
Q

An experiment began with 4 cells and ended with 128 cells. How many generations did the cell go through?

A

5

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4
Q

If you start out with a population density of 200 CFU/mL of a bacterium that divides every 20 minutes, what will the population density be at the end of two hours, assuming the cells are in the log phase of growth?

A

2^6 x 200 CFU/mL

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5
Q

Which of the following statements is true pertaining to the disk diffusion tests?

A

Clear zones around the colonies represent no growth in that particular area.

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6
Q

Which of the following is not an action of Penicillin?

A

Blocks the enzyme that catalyzes peptide chain elongation

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7
Q

Starvation proteins are produced by a culture during which portion of the growth curve?

A

Stationary Phase

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8
Q

This type of organism can live with or without oxygen, with no preference at all.

A

Facultative Anaerobe

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9
Q

A student noticed that a culture broth tube was very turbid at the bottom of the tube but completely clear at the top. What can they conclude about the organism?

A

The organism cannot produce SOD or catalase.

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10
Q

What kind of antibiotic is considered a “last resort” drug?

A

Vancomycin

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11
Q

Which is a false statement about microbial control methods?

A

Disinfectants can be used on human skin safely.

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12
Q

Which is true about moist heat?

A

Moist heat can destroy viruses and fungi.

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13
Q

What structures are used for protection against UV light and its harmful mutations?

A

Carotenoid pigments

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14
Q

Which is not a condition that influences the effectiveness of antimicrobial agents?

A

The linear relationship between concentration and effectiveness

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15
Q

Between antiseptics and disinfectants, which is considered more toxic?

A

Disinfectants

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16
Q

Select all the answers that are correct statements.

A

b. Waksman discovered the antibiotic streptomycin.
c. The minimum lethal concentration (MLC) is the lowest concentration of drugs from which organisms cannot recover when removed.

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17
Q

Which of the following is the best trait for an antibiotic to have?

A

Broad-spectrum, Bacteriostatic

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18
Q

Most bacterial and archaea cells divide using:

A

Binary Fission

19
Q

In order for septation to fully take place, what needs to happen

A

The genetic material must replicate.
The Z ring must be assembled.
Chromosome partitioning must occur.

20
Q

The higher the phenol coefficient value, then the _____ effective that the disinfectant is.

A

more

21
Q

Which of the following units is considered an intermediate filament homologue?

A

CreS

22
Q

Select all that apply about extremophiles and their characteristics

A

Halophiles prefer salt environments above 0.2 M NaCl.

Mesophiles can cause our flu-like symptoms.

23
Q

How do Gram-negative organisms communicate in their biofilms?

A

Through autoinducer moleculesc.

Through acylhomoserine lactone

24
Q

Which is not a possible reason for the stationary phase?

A

Programmed cell death or Apoptosis

25
Q

Which of the following statements is false?

A

Counting chambers can distinguish living from dead cells due to its ability to count both eukaryotes and prokaryotes.

26
Q

Which of the following is not a category of antimicrobial drugs?

A

Those that inhibit mRNA processing

27
Q

Which of the following is used to grow bacterial cultures continuously (fresh medium added continuously)?

A

Chemostat

28
Q

A bacterial population increases from 100 cells to 100,000,000 cells in 15 hours. What is the generation time of this culture?

A

45 minutes

29
Q

Select all the answers that are true.

A

Bacteriophages are viruses that could target and lyse bacterial pathogens.
Tetracycline inhibits protein synthesis.
Folic acid can be used to synthesize nucleic acid subunits.

30
Q

Which are characteristics of a continuous culture?

A

Continual removal of wastes
Maintaining cells in a constant stationary phase and biomass concentration
Constant supply of cells growing at a known rate

31
Q

Which of the following is true about biofilm? Select all that apply.

A

Heterogeneity leads to increased interactions and communications among the bacterium.
Quorum sensing is responsible for the symbiosis between bacterium and bioluminescence in squids.e. Gram-positive bacteria use oligopeptides for quorum sensing.

32
Q

Which of the following is not a reactive oxygen species?

A

Superoxide radical

33
Q

Why are sulfa drugs that block folic acid considered highly selectively toxic?

A

Bacteria must synthesis folic acid, while humans acquire it from their diet.

34
Q

Which antibacterial drug does not inhibit protein synthesis?

A

vancomycin

35
Q

Cocktail drugs have decreased the onset of drug resistance in viruses.

A

true

36
Q

Which method would best be used to remove microorganisms by physical screening?

A

Autoclaving

37
Q

Why is dry heat less effective than moist heat?

A

It requires higher temperatures and longer exposure times.

38
Q

Which of the following statements is true?

A

Thymine dimers prevent replication and transcription.

39
Q

Which of the following antibiotics is considered a metabolic inhibitor?

A

Trimethoprim

40
Q

Which is not a mechanism in which nucleic acid synthesis is inhibited?

A

Inhibition of transpeptidation

41
Q

Which of the following is true about anti-fungal drugs?

A

Superficial mycoses can be treated topically and orally

42
Q

Anti-HIV drugs can be:

A

Fusion inhibitors

Protease inhibitors

43
Q

Which of the following statements is true about chromosome partitioning?

A

ParA works to pull a copy of the DNA away after depolymerization.

44
Q

Which statement is true about antibiotics?

A

Aminoglycoside binds to the 30S subunit.

Microbiology (4 decks)

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