Test Answers on Chapter 20 – Flashcards
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Unlock answersPenicillin was considered a miriacle drug for all of the following reasons 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 a bacteria |
| A. It was the first antibiotic |
A drug that inhibits mitosis, such as griseofulvin, would be more effective against: ; A gram positive bacteria B Gram negative bacteria C fungi D wall-less bacteris E. Mycobacteria |
| C. Fungi |
Most of the available antimicrobial agents are effective against: A viruses B bacteria C fungi D protozoa E All of the above |
| B. Bacteria |
Antimicrobial peptides work by: ; A inhibiting protein synthesis B disrupting the plasma membrane C complementary base pairing with DNA D inhibiting cell-wall synthesis E hydrolyzing peptidoglycan |
| B Disrupting the plasma membrane |
In what ways are semisynthetic penicillins and natural penicillins alike? ; A both are broad spectrum B both are resistant to penicillinase C both are resistant to stomach acids D both are bactericidal D both are based on B-lactam |
| E. Both are based on B-lactam |
Which of the following antibiotics is not bactericidal? ; A aminoglycosides B cephalosporins C polyenes D rifampins E penicillin |
| C. Polyenes |
Which of the following does not belong with the others? ; A bacitracin B cephalosporin C monobactam D Penicillin E streptomcin |
| E. Streptomycin |
The antibiotic tetracycline binds to the 30s subunit of the ribosome as shown in figure 20.1. ;The effect is to: A prevent attachment of tRNA B prevent peptide bond formation C prevent transcription D stop teh ribosome from moving along the mRNA E. prevent attachment of tRNA and mRNA |
| B. prevent peptide bond formation |
The antibiotic cycloheximide binds to the 60s subunit of the ribosome as shown in figure 20.2 the effect is to: ; A prevent mRNA -ribosome binding in eukaryotes B prevent peptide bond formation in prokaryotes C prevent poypeptide elongation in eukaryotes D prevent transcription in prokaryotes E prevent ribosome formation in bacteria ; |
| C. Prevent polypeptide elongation in eukaryotes. |
Which of these antimicrobial agents has the fewest side effects: A streptomycin B tetracycline c penicillin D erythromycin E chloramphenicol |
| C. Penicillin |
Which of the following drugs does not act by competitive inhibition? A ethambutol B isoniazid C streptomycin D sulfonimide E tetracycline |
| C. Streptomycin |
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. Inhibition of RNA synthesis |
Which of the following antibiotics is recommended for use against gram-negative bacteria? A polyenes B bacitracin C cephalosporin D penicillin E polymyxin |
| E. Polymyxin |
Which of the following antimicrobial agents is recommended for use against fungal infections? ; A amphotericin B B bacitracin C Cephalosporin D penicillin E polymyxin |
| A. Amphotericin B |
More than half of our antibiotics are ; A produced by fungi B produced by bacteria C synthesized in laboratories D produced by Fleming E Produced by eukaryotic organisms |
| B Produced by bacteria |
Which compound would be the most useful to treat candidiasis? A uracil B thymin C flucytosine D guanine E Penicillin |
| C. Flucytosine |
Which of the following antibiotics are used to treat fungal infections; 1 aminoglycosides 2cephalosporins 3 griseofulvin 4 polyenes 5 bacitracin A 1,2,3 B 3, 4 C 3,4,5, D 4,5 E all of the antibiotics |
| B. 3,4 |
Which of the following antibiotics does not interfere with cell wall synthesis? A cephalosporins B macrolides C natural penicillins d senisyntheti penicillins E vancomycin |
| B. Macrolides |
The antimicrobial drugs with the broadest spectrum of activity are: A aminoglycosides B chloramphenicol C lincomycin D macrolides E tetracyclines |
| E. 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. Interferon inhibits interferon |
Protozoan and helminthic diseases are difficult to treat because: A their cells are structurally and functionally similar to human cells B They replicate insie human cells C They dont have ribosomes D They don't reproduce E They have more genes than bacteria |
| A. Their cells are structurally and functionally similar to human cells |
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. Streptococcus pyogenes |
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 during 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. It is found only in gram-negative bacteria. |
Which of the following does not constitute an advantage of using two antibiotics together?
A it can prevent drug resistance B It lessens 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. Two are always twice as effective as one |
The structure of the influenza drug Tamiflu and Salic acid, the substrate for influenza virus's neuramidase, are shown in figure 20.6. ;What is the method of action of Tamiflu? ; A inhibits cell wall synthesis B inhibits plasma membrane synthesis C inhibits synthesis of neuramidase D competitive inhibition E prevents synthesis of virus spikes |
| D. Competitive inhibition |
The antibiotic chloramphenicol Binds to the 50s subunit of the ribosome as shown in figure 20.3. ;The effect is to ; A prevent attachment of tRNA B prevent peptide bond formation C prevent transcrition D stop ribosome from moving along the mRNA E prevent polypeptide formation in eukaryotes. |
| A. Prevent attachment of tRNA |
Drug resistance occurs; ; A because bacteria are normal microbiota B when antibiotics are used indiscriminately C against antibiotics and not against synthetic chemotherapeutic agents D when antibiotics are taken after symptons disappear E all of the above ; |
| B. when antibiotics are used indiscriminately |
Which of the following would be selective against the tubercle bacillus? A bacitracin - inhibits peptidoglycan synthesis B ethambutol-inhibits mycolic acid synthesis C streptogramin inhibits protein synthesis D Streptomycin inhibits protein synthesis D Vancomycin inhibits peptidoglycan synthesis |
| B. ethambutol- inhibits mycolic acid synthesis |
In the presence of penicillin, a cell dies because A it lacks a cell wall B it plasmolyzes C it undergoes osmotic lysis D it lacks a cell membrane E its contents leak out |
| C. It undergoes osmotic lysis |
Lamisil is an allylamine used to treat dermatonycoses. ;Lamisil's method of action is similar to that of A polymyxin B B azole antibiotics C echinocandins D griseofulvin E bactracin |
| B Azole antibiotics |
Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against A gram-negative bacteria B gram-positive bacteria C helminths D mycobacterium tuberculosis E viruses |
| C Helminths |
Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is false? A they cause mutations B they are used against viral infections C they can affect hot cell DNA D they are too dangerous to use E they interfere with protein synthesis |
| D They are too dangerous to use. |
Which of the following does not affect eukaryotic cells? A antiprotozoan drugs B antihelminthic drugs C antifungal drugs D nucleotide analogs E semisynthetic penicillins |
| E. semisynthetic penicillins |
Mebendazole is used to treat cestode infections. It interfers with microtubule formation; therefore, it would not affect
A bacteria B fungi C helminths D human cells E protozoa
|
| A. bacteria |
Which of the following antibiotics causes misreading of mRNA A aminoglycoside-changes shape of 30s units B chloramphenicol-inhibits peptide bonds at 50s subunit C oxazolidinine-prevents formation of 70s ribosome D streptogamin - prevents release of peptide from 70s ribosome E tetracyclines - bind with 30s subunit |
| A. aminoglycoside changes shape of 30s units |
The antibiotic actinomycin D binds between adjacent G-C pairs, thus interfering with A transcription B translation C cellular respiration D plasma membrane function E peptide bond formation
|
| A. transcription |
Use of antibiotics in animal feed leads to antibiotic-resistance bacteria because A bacteria from other animals replace those killed by the antibiotics B the few surviving bacteria that are affected by the antibiotics develop immunity to the antibiotics, which they pass on to their progeny C the antibiotics cause new mutations to occur in the surviving bacteria which results in reistance D the antibiotics kill susceptible bacteria but the few that are naturally resistant live and reproduce and their progeny repopulate the host E the antibiotics persist in soil and water |
| D the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal. |
