Penicillin was considered a "miracle drug" for all of the following EXCEPT. A. It was the first antibiotic. B. It doesn't affect eukaryotic cells. C. It inhibits gram-positive cell wall synthesis. D. It has selective toxicity. E. It kills bacteria.
A.
A drug that inhibits mitosis, such as griseofulvin, would be more effective against?
Fungi
Most of the available antimicrobial agents are effective against?
Bacteria
Antimicrobial peptides work by?
Disrupting the plasma membrane.
In what way are semisynthetic penicillins and natural penicillins alike?
D)
Which of the following antibiotics is NOT bactericidal? A) Aminoglycosides. B) Cephalosporins. C) Polyenes. D) Rifampins. E) Penicillin.
C.
Which one of the following does NOT belong with the others? A) Bacitracin. B) Cephalosporin. C) Monobactam. D) Penicillin. E) Streptomycin.
E.
The antibiotic tetracycline binds to the 30S subunit of the ribosome as shown in Figure 20.1. The effect is to?
Interfere with the attachment of the tRNA to the mRNA ribosome complex.
The antibiotic cycloheximide binds to the 60S subunit of the ribosome as shown in figure 20.2. The effect is to?
Prevent polypeptide elongation in eukaryotes.
Which of these antimicrobial agentshas the fewest side effects? A) Streptomycin. B) Tetracycline. C) Penicillin. D) Erythromycin. E) Chloramphenicol.
C.
Which of the following drugs does NOT act by competitive inhibition? A) Ethambutol. B) Isoniazid. C) Streptomycin. D) Sulfonamide. E) Tetracycline.
C.
Which of the following methods of action would be bacteriostatic? A) Competitive inhibition with folic acid synthesis. B) Inhibition of RNA synthesis. C) Injury to plasma membrane. D) Inhibition of cell wall synthesis. E) Competitive inhibition with DNA gyrase.
B.
Which of the following antibiotics is recommended for use against gram-negative bacteria? A) Polyenes. B) Bacitracin. C) Cephalosporin. D) Penicillin. E) Polymyxin.
E.
Which of the following antimicrobial agents is recommended for use against fungal infections? A) Amphotericin. B) Bacitracin. C) Cephalosporin. D) Penicillin. E) Polymyxin.
A.
In table 20.1, the minimal bactericidal concentration of antibiotic X is?
15
In table 20.1, the minimal inhibitory concentration of antibiotic X is?
10
More than half of our antibiotics are?
Produced by bacteria.
The antibiotic Chloramphenicol binds to 50S: subunit of the ribosome as shown in figure 20.3. The effect is to.
Prevent attachment of tRNA.
The antibiotic Streptomycin binds to 30S subunit of the ribosome as shown in figure 20.4. The effect is to?
Cause misreading of mRNA in 70S ribosomes.
Which compound would be the most useful to treat candidiasis? A) Uracil. B) Thymine. C) Flucytosine. D) Guanine. E) Penicillin.
C.
Which of the following antibiotics are used to treat fungal infections. A) Aminoglycosides. B) Cephalosporins. C) Griseofulvin. D) Polyenes. E) Bacitracin.
C and D.
Which of the following antibiotics does NOT interfere with cell wall synthesis? A) Cephalosporins B) Macrolides. C) Natural penicillins. D) Semisynthetic penicillins. E) Vancomycin.
B.
The antimicrobial drugs with the broadest spectrum of activity are?
Tetracyclines
Which of the following statements is false? A) Fluoroquinolone inhibits DNA synthesis. B) Acyclovir inhibits DNA synthesis. C) Amantadine inhibits release of viral nucleic acid. D) Interferon inhibits glycolysis. E) Azoles inhibit plasma membrane synthesis.
D.
Protozoan and heminthic diseases are difficult to treat because? A) Their cells are structurally and functionally similar to human cells. B) They replicate inside human cells. C) They don't have ribosomes. D) They don't reproduce. E) They have more genes than bacteria.
A.
Which of the following organisms would most likely be sensitive to natural penicillin? A) L forms. B) Streptococcus pyogenes. C) Penicillinase producing Neisseria gonorrhoeae. D) Penicillium. E) Mycoplasma
B.
Which of the following statements about drug resistance is false? A) It may be carried on a plasmid. B)It may be transferred from one bacterium to another drug conjugation. C) It may be due to enzymes that degrade some antibiotics. D) It is found only in gram-negative bacteria. E) It may be due to increased uptake of a drug.
D.
Which of the following does NOT constitute an advantageof using two antibiotics together. A) It can prevent drug resistance. B) It less3ns the toxicity of individual drugs. C) Two are always twice as effective as one. D) It allows treatment to be provided prior to diagnosis. E) All of the above are advantages.
C.
Drug resistance occurs
When antibiotics are used indiscriminately.
In Table 20.2 the most effective antibiotic was
Row D-10mm
In table 20.2 the antibiotic that exhibited bactericidal action was
E) Can't tell.
In table 20.2 which antibiotic would be most useful for treating a Salmonella infection.
E) Can't tell.
Which of the following would be selective against the tubercale bacillus?
B) Ethambutol- inhibits mycolic acid synthesis.
In the presence of penicillin a cell dies because.
It undergoes osmotic lysis
Lamisil is an allylamine used to treat dermatomycoses. Lamisil's method of action is similar to that of?
Azole antibiotics.
Niclosamide prevents ATP generation in mitrochondria. You would expect this drug to be effective against?
Helminths
The data in table 20.3 show that these bacteria
Developed resistance to antibiotics.
Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is false?
They are too dangerous to use.
The substrate for transpeptidase used to synthesize peptidoglycan is shown in figure 20.5. Which of the drugs shown would inhibit peptidoglycan synthesis?
D.
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?
Competitive inhibition.
Which of the following does NOT affect eukaryotic cells?
Semisynthetic penicillins.
Mebendazole is used to treat cestode infections. It interferes with microtubule formation, therefore, oit would NOT affect
Bacteria.
Which of the following antibiotics causes misreading of mRNA?
Aminoglycoside-changes shape of 30S units
The antibiotic actinomyocinD binds between adjacent G-C pairs, thus interfering with
Transcription.
Use of antibiotics in animal feed leads to antibiotic resistant bacteria because.
The antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
