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micro last stretch > chapter 20 > Flashcards

chapter 20 Flashcards

1
Q

Penicillin was considered a “miracle drug” for all of the following reasons EXCEPT

 	It was the first antibiotic. 
 	It doesn't affect eukaryotic cells. 
 	It inhibits gram-positive cell wall synthesis. 
 	It has selective toxicity. 
 	It kills bacteria.
A

It was the first antibiotic.

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2
Q

A drug that inhibits mitosis, such as griseofulvin, would be more effective against

 	Gram-positive bacteria. 
 	Gram-negative bacteria. 
 	Fungi. 
 	Wall-less bacteria. 
 	Mycobacteria.
A

Fungi.

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3
Q

Most of the available antimicrobial agents are effective against

 	Viruses. 
 	Bacteria. 
 	Fungi. 
 	Protozoa. 
 	All of these.
A

Bacteria.

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4
Q

Antimicrobial peptides work by

 	Inhibiting protein synthesis. 
 	Disrupting the plasma membrane. 
 	Complementary base pairing with DNA. 
 	Inhibiting cell-wall synthesis. 
 	Hydrolyzing peptidoglycan.
A

Disrupting the plasma membrane.

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5
Q

In what way are semisynthetic penicillins and natural penicillins alike?

 	Both are broad spectrum. 
 	Both are resistant to penicillinase. 
 	Both are resistant to stomach acids. 
 	Both are bactericidal. 
 	Both are based on  -lactam.
A

Both are based on -lactam.

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6
Q

Which of the following antibiotics is NOT bactericidal?

 	Aminoglycosides 
 	Cephalosporins 
 	Polyenes 
 	Rifampins 
 	Penicillin
A

Polyenes

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7
Q

Which one of the following does NOT belong with the others?

 	Bacitracin 
 	Cephalosporin 
 	Monobactam 
 	Penicillin 
 	Streptomycin
A

Streptomycin

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8
Q

Figure 20.1

The antibiotic tetracycline binds to the 30S subunit of the ribosome as shown in Figure 20.1. The effect is to

 	Prevent attachment of tRNA. 
 	Prevent peptide bond formation. 
 	Prevent transcription. 
 	Stop the ribosome from moving along the mRNA. 
 	Prevent attachment of tRNA and mRNA.
A

Prevent peptide bond formation.

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9
Q

Figure 20.2

The antibiotic cycloheximide binds to the 60S subunit of the ribosome as shown in Figure 20.2. The effect is to

Prevent mRNA-ribosome binding in eukaryotes.
Prevent peptide bond formation in prokaryotes.
Prevent polypeptide elongation in eukaryotes.
Prevent transcription in prokaryotes.
Prevent ribosome formation in bacteria.

A

Prevent polypeptide elongation in eukaryotes.

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10
Q

Which of these antimicrobial agents has the fewest side effects?

 	Streptomycin 
 	Tetracycline 
 	Penicillin 
 	Erythromycin 
 	Chloramphenicol
A

Penicillin

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11
Q

Which of the following drugs does NOT act by competitive inhibition?

 	Ethambutol 
 	Isoniazid 
 	Streptomycin 
 	Sulfonamide 
 	Tetracycline
A

Streptomycin

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12
Q

Which of the following methods of action would be bacteriostatic?

 	Competitive inhibition with folic acid synthesis 
 	Inhibition of RNA synthesis 
 	Injury to plasma membrane 
 	Inhibition of cell wall synthesis 
 	Competitive inhibition with DNA gyrase
A

Inhibition of RNA synthesis

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13
Q

Which of the following antibiotics is recommended for use against gram-negative bacteria?

 	Polyenes 
 	Bacitracin 
 	Cephalosporin 
 	Penicillin 
 	Polymyxin
A

Polymyxin

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14
Q

Which of the following antimicrobial agents is recommended for use against fungal infections?

 	Amphotericin B 
 	Bacitracin 
 	Cephalosporin 
 	Penicillin 
 	Polymyxin
A

Amphotericin B

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15
Q

In Table 20.1, the minimal bactericidal concentration of antibiotic X is

 	2  g/ml. 
 	10  g/ml. 
 	15  g/ml. 
 	25  g/ml. 
 	Can't tell.
A

15 g/ml.

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16
Q

In Table 20.1, the minimal inhibitory concentration of antibiotic X is

 	2  g/ml. 
 	10  g/ml. 
 	15  g/ml. 
 	25  g/ml. 
 	Can't tell.
A

10 g/ml.

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17
Q

More than half of our antibiotics are

 	Produced by fungi. 
 	Produced by bacteria. 
 	Synthesized in laboratories. 
 	Produced by Fleming. 
 	Produced by eukaryotic organisms.
A

Produced by bacteria.

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18
Q

Figure 20.3

The antibiotic chloramphenicol binds to the 50S subunit of the ribosome as shown in Figure 20.3. The effect is to

Prevent attachment of tRNA.
Prevent peptide bond formation.
Prevent transcription.
Stop the ribosome from moving along the mRNA.
Prevent polypeptide formation in eukaryotes.

A

Prevent attachment of tRNA.

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19
Q

Figure 20.4

The antibiotic streptomycin binds to the 30S subunit of the ribosome as shown in Figure 20.4. The effect is to

Cause misreading of mRNA in 70S ribosomes.
Prevent binding of tRNA in eukaryotes.
Prevent polypeptide elongation in eukaryotes.
Prevent peptide bond formation in prokaryotes.
Prevent binding of tRNA in eukaryotes.

A

Cause misreading of mRNA in 70S ribosomes.

20
Q

Which compound would be the most useful to treat candidiasis?

 	Uracil 
 	Thymine 
 	Flucytosine 
 	Guanine 
 	Penicillin
A

Flucytosine

21
Q

Which of the following antibiotics are used to treat fungal infections?

 	1, 2, and 3 
 	3 and 4 
 	3, 4, and 5 
 	4 and 5 
 	All of the antibiotics
A

3 and 4

22
Q

Which of the following antibiotics does NOT interfere with cell wall synthesis?

 	Cephalosporins 
 	Macrolides 
 	Natural penicillins 
 	Semisynthetic penicillins 
 	Vancomycin
A

Macrolides

23
Q

The antimicrobial drugs with the broadest spectrum of activity are

 	Aminoglycosides. 
 	Chloramphenicol. 
 	Lincomycin. 
 	Macrolides. 
 	Tetracyclines.
A

Tetracyclines.

24
Q

Which of the following statements is false?

Fluoroquinolone inhibits DNA synthesis.
Acyclovir inhibits DNA synthesis.
Amantadine inhibits release of viral nucleic acid.
Interferon inhibits glycolysis.
Azoles inhibit plasma membrane synthesis.

A

Interferon inhibits glycolysis.

25
Q

Protozoan and helminthic diseases are difficult to treat because

 	Their cells are structurally and functionally similar to human cells. 
 	They replicate inside human cells. 
 	They don't have ribosomes. 
 	They don't reproduce. 
 	They have more genes than bacteria.
A

Their cells are structurally and functionally similar to human cells.

26
Q

Which of the following organisms would most likely be sensitive to natural penicillin?

 	L forms 
 	Streptococcus pyogenes 
 	Penicillinase-producing Neisseria gonorrhoeae 
 	Penicillium 
 	Mycoplasma
A

Streptococcus pyogenes

27
Q

Which of the following statements about drug resistance is false?

It may be carried on a plasmid.
It may be transferred from one bacterium to another during conjugation.
It may be due to enzymes that degrade some antibiotics.
It is found only in gram-negative bacteria.
It may be due to increased uptake of a drug.

A

It is found only in gram-negative bacteria.

28
Q

Which of the following does NOT constitute an advantage of using two antibiotics together?

It can prevent drug resistance.
It lessens the toxicity of individual drugs.
Two are always twice as effective as one.
It allows treatment to be provided prior to diagnosis.
All of these are advantages.

A

Two are always twice as effective as one.

29
Q

Drug resistance occurs

Because bacteria are normal microbiota.
When antibiotics are used indiscriminately.
Against antibiotics and not against synthetic chemotherapeutic agents.
When antibiotics are taken after the symptoms disappear.
All of these.

A

When antibiotics are used indiscriminately.

30
Q

In Table 20.2, the most effective antibiotic tested was

 	A. 
 	B. 
 	C. 
 	D. 
 	Can't tell.
A

D.

31
Q

In Table 20.2, the antibiotic that exhibited bactericidal action was

 	A. 
 	B. 
 	C. 
 	D. 
 	Can't tell.
A

Can’t tell.

32
Q

In Table 20.2, which antibiotic would be most useful for treating a Salmonella infection?

 	A 
 	B 
 	C 
 	D 
 	Can't tell.
A

Can’t tell.

33
Q

Which of the following would be selective against the tubercle bacillus?

Bacitracin - inhibits peptidoglycan synthesis
Ethambutol - inhibits mycolic acid synthesis
Streptogramin - inhibits protein synthesis
Streptomycin - inhibits protein synthesis
Vancomycin - inhibits peptidoglycan synthesis

A

Ethambutol - inhibits mycolic acid synthesis

34
Q

In the presence of penicillin, a cell dies because

 	It lacks a cell wall. 
 	It plasmolyzes. 
 	It undergoes osmotic lysis. 
 	It lacks a cell membrane. 
 	Its contents leak out.
A

It undergoes osmotic lysis.

35
Q

Lamisil is an allylamine used to treat dermatomycoses. Lamisil’s method of action is similar to that of

 	Polymyxin B. 
 	Azole antibiotics. 
 	Echinocandins. 
 	Griseofulvin. 
 	Bacitracin.
A

Azole antibiotics.

36
Q

Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against

 	Gram-negative bacteria. 
 	Gram-positive bacteria. 
 	Helminths. 
 	Mycobacterium tuberculosis. 
 	Viruses.
A

Helminths.

37
Q

Table 20.3
The following data were obtained from a broth dilution test:

The data in Table 20.3 show that these bacteria

Can be subcultured.
Developed resistance to antibiotics.
Were killed by 0.125 g/ml of antibiotic X.
Were killed by 0.5 g/ml of antibiotic X.
Were resistant to 1.0 g/ml at the start of the experiment.

A

Developed resistance to antibiotics.

38
Q

Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is false?

 	They cause mutations. 
 	They are used against viral infections. 
 	They can affect host cell DNA. 
 	They are too dangerous to use. 
 	They interfere with protein synthesis.
A

They are too dangerous to use.

39
Q

Figure 20.5

The substrate for transpeptidase used to synthesize peptidoglycan is shown in Figure 20.5. Which of the drugs shown would inhibit peptidoglycan synthesis?

 	a 
 	b 
 	c 
 	d 
 	e
A

d

40
Q

Figure 20.6

The structures of the influenza drug Tamiflu and sialic acid, the substrate for influenza virus s neuramidase, are shown in Figure 20.6. What is the method of action of Tamiflu?

 	Inhibits cell wall synthesis 
 	Inhibits plasma membrane synthesis 
 	Inhibits synthesis of neuramidase 
 	Competitive inhibition 
 	Prevents synthesis of virus spikes
A

Competitive inhibition

41
Q

Which of the following does NOT affect eukaryotic cells?

 	Antiprotozoan drugs 
 	Antihelminthic drugs 
 	Antifungal drugs 
 	Nucleotide analogs 
 	Semisynthetic penicillins
A

Semisynthetic penicillins

42
Q

Mebendazole is used to treat cestode infections. It interferes with microtubule formation; therefore, it would NOT affect

 	Bacteria. 
 	Fungi. 
 	Helminths. 
 	Human cells. 
 	Protozoa.
A

Bacteria.

43
Q

Which of the following antibiotics causes misreading of mRNA?

Aminoglycoside - changes shape of 30S units
Chloramphenicol - inhibits peptide bonds at 50S subunit
Oxazolidinone - prevents formation of 70S ribosome
Streptogamin - prevents release of peptide from 70S ribosome
Tetracyclines - bind with 30S subunit

A

Aminoglycoside - changes shape of 30S units

44
Q

The antibiotic actinomycin D binds between adjacent G-C pairs, thus interfering with

 	Transcription. 
 	Translation. 
 	Cellular respiration. 
 	Plasma membrane function. 
 	Peptide bond formation.
A

Transcription.

45
Q

Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because

Bacteria from other animals replace those killed by the antibiotics.
The few surviving bacteria that are affected by the antibiotics develop immunity to the antibiotics, which they pass on to their progeny.
The antibiotics cause new mutations to occur in the surviving bacteria, which results in resistance to antibiotics.
The antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
The antibiotics persist in soil and water.

A

The antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.

micro last stretch (6 decks)

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