MED CHEM REVIEW

MED CHEM REVIEW - MED CHEM REVIEW ALL of the following...

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ALL of the following choices after the questions are CORRECT answers to the question. The incorrect answers are not listed or were changed to make them correct. These are all old final exam questions compiled together. 1. Which of the following statements regarding the therapeutic index (TI) is correct? a) TI= LD50/ED50 b) TI= maximum tolerated dose/minimum effective dose c) TI= toxic dose/effective dose d) The higher the TI, the safer the drug 2. Which of the following is likely to lead to antibiotic resistance? a) Increased cellular efflux of the drug b) Decreased affinity of the target to the drug c) Increased enzymatic degradation of the drug d) Decreased metabolic activation of the drug e) Increased amount of the target of the drug f) Decreased cellular uptake of the drug g) Increased modification of the drug 3. Which of the following is unlikely to lead to antibiotic resistance? a) Increased cellular uptake of the drug b) Decreased cellular efflux of the drug c) Increased affinity of the target to the drug 4. Which of the following mechanisms is responsible for isoniazid resistance? a) Lack of metabolic activation b) Defect in the catalase/peroxidase enzyme system of M Tuberculosis which catalyzes metabolic activation by oxidative metabolism 5. Which of the following mechanisms is responsible for erythromycin resistance? a) Decreased affinity of the target b) Altered ribosomal RNA structure c) Methylation of a specific adenine in ribosomal RNA by a methyltransferase enzyme(which prevents binding of the antibiotic to the 50S ribosomal subunit 6. Modification of a drug structure by acetylation and phosphorylation and adenylation plays a role in the bacterial resistance against which of the following antibiotics? (These modifications alter or destroy the positively charged character of these antibiotics, so they can no longer bind to their ribosomal targets) a) aminoglycosides (streptomycin, kanomycin) 7. Which of the following antibiotics works by inhibition of the bacterial protein biosynthesis? (they bind to bacterial ribosomes, causing a conformational change that is detrimental to the synthesis of bacterial proteins) a) streptomycin b) erythromycin c) tetracycline d) chloramphenicol 8. Which of the following antibiotics works by inhibition of the bacterial cell wall biosynthesis? a) penicillin G b) cephalosporin C c) vancomycin d) D-cycloserine e) Isoniazide (inhibits cell wall synthesis in mycobacteria, causing TB) 9. Bacterial resistance to the antibiotic vancomycin (called the last resort against multi-drug resistant bacteria) was shown to involve the replacement of the D-ala D-ala moiety with the D-ala D- lactate in the cell wall precursor that serves as the target of the drug. This amounts to a change of an amide linkage with an ester, and the resultant loss of a critical interaction with a specific carbonyl oxygen of vancomycin. The loss of which of the following bond types may be the cause of resistance? a)
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MED CHEM REVIEW - MED CHEM REVIEW ALL of the following...

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