51-100 Flashcards by Hana Nafuar

Which of the following antibacterial agents can disrupt the synthesis of essential proteins and enzyme required for the cell’s survival?
a. Sulfonamides
b. Polymyxins
c. Penicillins
d. Rifamycin
e. Nalidixic acid

Rifamycin

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This antibacterial agent can inhibit the nucleic acid transcription and replication which prevents
cell division and.or protein synthesis.
a. Sulfonamides
b. Polymyxins
c. Penicillins
d. Rifamycin
e. Nalidixic acid

Nalidixic acid

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For questions 53-55, refer to the general structure of sulphonamides below: Which part of the drug’s structure is essential for drug activity?
a. Aromatic ring
b. Sulphonamide group
c. P-amino group
d. A and B only
e. All of the above

All of the above

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Which of the following statements is/are correct regarding the structure-activity relationship of
sulphonamides?
I. The p-amino group must be unsubstituted unless it is a prodrug or when the body can further
metabolize it to generate the active compound.
II. Extra substitution of the aromatic ring increases activity.
III. The sulphonamide nitrogen must be primary or secondary.

I and III

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Which part of the drug molecule can only be varied to retain the antibacterial activity?
a. Aromatic ring
b. p-amino group
c. R2
d. A and B
e. None of the choices

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A sulphonamide used in combination with pyrimethamine in the treatment of Malaria.
a. Sulfadiazine
b. Sulfathiazole
c. Sulfadoxine
d. Sulfamethoxazole
e. Sulfones

Sulfadoxine

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It is an orally active dyaminopyridine structure which has proved to be highly selective
antibacterial and antimalarial agent often given in conjunction with sulfamethoxazole. It inhibits the enzyme dihydrofolate reductase leading to the inhibition of DNA synthesis and cell growth.
a. Pyrimethamine
b. Trimethoprim
c. Pralidoxime
d. Cotrimoxazole
e. Fansidar

Trimethoprim

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Successfully isolated penicillin using processes such as freeze-drying and chromatography.
a. Alexander Flemming
b. Florey and Chain
c. Dorothy Hodgkins
d. Beechams
e. None of the above

Florey and Chain

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Below is the general structure of penicillins. Which part of its structure is not essential for activity?
a. The free carboxylic acid
b. The strained B-lactam ring
c. The acyl amino side chain
d. The bicyclic system
e. The sulphur atom

Sulphur atom

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Addition of electron-withdrawing group into the acyl side chain of penicillin structure will render
the drug
a. resistant to acid hydrolysis
b. Protected from B-lactamase enzymes
c. Broaden the spectrum of activity
d. A and B only
e. All of the above

resistant to acid hydrolysis

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What is the effect of steric shields to the penicillin structure?
a. It will make the drug stable in acidic conditions.
b. It will be protected from B-lactamase enzymes
c. It will have a broad spectrum of activity
d. All of the above
e. None of the above

It will be protected from B-lactamase enzymes

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This drug is a penicillin analogue with isoxazolyl incorporated in the acyl side chain making it
useful against Staphylococcus aureus infections and acid resistant.
a. Flucloxacillin
b. Ampicillin
c. Carbenicillin
d. Piperacillin
e. Tazobactam

Flucloxacillin

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Which of the following broad-spectrum penicillin analogues do not have a urea functional group
at the alpha-position?
a. Azlocillin
b. Mezlocillin
c. Ticarcillin
d. Piperacillin
e. None of the choices

Ticarcillin

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Which of the following broad spectrum penicillin analogues has carboxylic acid group in the acyl
side chain?
a. Azlocillin
b. Mezlocillin
c. Ticarcillin
d. Piperacillin
e. None of the choices

Ticarcillin

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Which of the following amino acids are the biosynthetic precursors of penicillin?
a. Alanine
b. Cysteine
c. Valine
d. A and B only
e. B and C only

Cystein and Valine

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Which of the following statements is incorrect regarding the chemical structure of cephalosporins?
a. Cephalosporins contain a bicyclic system containing a 4-membered B-lactam ring.
b. The B-lactam ring of cephalosporins is fused to five-membered dihydrothiazine ring.
c. Biosynthetic precursors of its skeleton is the same as that of penicillins.
d. A and B
e. B and C

The B-lactam ring of cephalosporins is fused to five-membered dihydrothiazine ring.

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Which of the following statements correctly describe/s the structure of carbapenems such as
imipenem and meropenem?
a. Absence of sulphur atom in the bicyclic ring system
b. It has no acyl amino side chain
c. The lactam ring is fused to a sic membered ring
d. A and B only
e. All of the above

a. Absence of sulphur atom in the bicyclic ring system
b. It has no acyl amino side chain

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Clavulanic acid is a beta-lactamase inhibitor used in combination with amoxicillin and other Blactamase antibiotics. Which of the following statements correctly describe clavulanic acid?
a. Clavulanic acid has a strained lactam ring in its structure.
b. It has no amino acyl side chain compared to other B-lactam antibiotics
c. Sulfur atom is essential for its activity against lactamases
d. A and B only
e. All of the above

a. Clavulanic acid has a strained lactam ring in its structure.
b. It has no amino acyl side chain compared to other B-lactam antibiotics

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Clavulanic acid, Sulbactam and tazobactam are B-lactamase inhibitors that act as suicide substrates are administered with B-lactam antibiotics to prevent their degradation. Which of the following combinations are correctly matched to their brand names?
a. Sulbactam + Piperacillin = Zosyn
b. Tazobactam + Ticarcillin = Timentin
c. Clavulanic acid + amoxicillin = Augmentin
d. A and B only
e. A and C only

Clavulanic acid + amoxicillin = Augmentin

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This antibiotic was isolated from Streptomyces garyphalus and inhibits bacterial cell wall synthesis by mimicking the structure of D-Alanine and inhibiting the enzymes L-Alanine racemase and D-Ala-D-Ala ligase.
a. Bacitracin
b. Vancomycin
c. D-cycloserine
d. Aztreonam
e. Teicoplanin

D-cycloserine

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A polypeptide complex produced from Bacillus subtilis that binds and inhibits the carrier lipid
responsible for carrying the cell wall components across the cell membrane.
a. Bacitracin
b. Vancomycin
c. D-cycloserine
d. Aztreonam
e. Teicoplanin

Bacitracin

A glycopeptide antibiotic isolated from Streptomyces orientalis.
a. Bacitracin
b. Vancomycin
c. D-cycloserine
d. Valinomycin
e. Teicoplanin

Vancomycin

A glycopeptide antibiotic isolated from Actinomyces teichomyceticus
a. Bacitracin
b. Vancomycin
c. D-cycloserine
d. Aztreonam
e. Teicoplanin

Teicoplanin

An antibiotic composed of 16 amino acids that is described as a ‘tunnelling’ molecule that act on
the plasma membrane and result in the uncontrolled movement of ions across cell membrane leading to cell death.
a. Daptomycin
b. Gramicidin A
c. Valinomycin
d. Polymyxin B
e. All of the above

Gramicidin A

An ionophore antibiotic with a cyclic structure obtained from Streptomyces fermentation that acts on the plasma membrane structure by allowing the uncontrolled movement of ions across the cell membrane. This ionophore is specific for potassium ions over sodium ions. a. Daptomycin b. Gramicidin A c. Valinomycin d. Polymyxin B e. All of the above

Valinomycin

A polypeptide antibiotic derived from Bacillus polymyxa which can cause leakage of small molecules such as nucleosides from the cell resulting to cell death. a. Daptomycin b. Gramicidin A c. Valinomycin d. Polymyxin B e. All of the above

Polymyxin B

A cyclic lipopeptide derived from a bacterial strain of Streptomyces roseosporus and works by disrupting multiple functions of bacterial cell membrane. a. Daptomycin b. Gramicidin A c. Valinomycin d. Polymyxin B e. All of the above

Daptomycin

A bactericidal protein synthesis inhibitor that was isolated from Streptomyces griseus. This antibiotic contains a carbohydrate and basic amine groups in its structure. a. Chlortetracycline b. Streptomycin c. Chloramphenicol d. Lincomycin e. Erythromycin

Streptomycin

A bacteriostatic antibiotic which inhibits protein synthesis by binding to the 30s subunit of ribosomes and preventing aminoacyl tRNA from binding. This drug was isolated from Streptomyces aureofasciens. a. Chlortetracycline b. Streptomycin c. Chloramphenicol d. Lincomycin e. Erythromycin

Chlortetracycline

Which of the following antibiotics has a large lactone ring, a ketone group and a glycosidically linked amino sugar in its structure? a. Chlortetracycline b. Streptomycin c. Chloramphenicol d. Lincomycin e. Erythromycin

Erythromycin

Clindamycin, a sulphur containing antibiotic, must not be given with which of the following drugs because of having the same binding site at the ribosomes? a. Chlortetracycline b. Chloramphenicol c. Erythromycin d. A and B only e. B and C only

Chloramphenicol and Erythromycin

Quinupristin and Dalfupristin are streptogramins isolated from a. Streptomyces griseus b. Streptomyces pristinaespiralis c. Acremonium chrysogenu d. Streptomyces nodosus e. Streptomyces erythreus

Streptomyces pristinaespiralis

Which of the following drug is an oxazolidinone that can prevent the formation of 70s ribosome by binding to the 50s subunit? a. Quinupristin b. Linezolid c. Ofloxacin d. Metronidazole e. Proflavine

Linezolid

Nalidixic acid was the first therapeutically agent in the class of compounds that inhibits topoisomerase enzymes, resulting in inhibition of replication and transcription. Which of the following is related to nalidixic acid? a. Quinupristin b. Linezolid c. Ofloxacin d. Metronidazole e. Proflavine

Ofloxacin

An aminoacridine agent used topically to treat deep surface wounds. It can interact directly with bacterial DNA by intercalation. a. Quinupristin b. Linezolid c. Ofloxacin d. Metronidazole e. Proflavine

Proflavine

The antibiotic isolated from Streptomyces mediterranei which inhibits Gram positive bacteria and works by binding noncovalently to DNA-dependent RNA polymerase and inhibiting the start of RNA synthesis. The flat naphthalene ring and several of the hydroxyl groups in its structure are essential for activity, and the drug exists in as zwitterions giving it good solubility in both aqueous acid and lipids. a. Rifamycin B b. Methenamine c. Metronidazole d. Isoniazid e. Nitrofurantoin

Rifamycin B

A nitroimidazole structure introduced as an anti-protozoal agent and later became anti bacterial agent. Its mechanism of action involves the drug entering the bacterial cell wall where the nitro group is reduced and free radicals are formed and act on DNA. a. Rifamycin B b. Methenamine c. Metronidazole d. Isoniazid e. Nitrofurantoin

Metronidazole

A drug used to treat urinary tract infections where it degrades in acid conditions to give formaldehyde as the active agent. a. Rifamycin B b. Methenamine c. Metronidazole d. Isoniazid e. Nitrofurantoin

Methenamine

An antiviral drug that has a nucleoside-like structure and contains the same nucleic acid base as deoxyguanosine, but lacks the complete sugar ring. It specifically inhibits viral DNA polymerase and used in the treatment of infections due to herpes simplex 1 and 2 as well as varicella-zoster viruses. a. Acyclovir b. Idoxuridine c. Podophyllotoxin d. Fomivirsen e. Imiquimod

Acyclovir

Which of the following is the valine ester prodrug of acyclovir useful in the treatment of varicella zoster virus infections? a. Cidofovir b. Penciclovir c. Valaciclovir d. Famciclovir e. Ganciclovir

Valaciclovir

Which of the following antiviral drug is an analogue of deoxythymidine used in the treatment of herpes keratitis? The triphosphate form of this drug inhibits viral DNA polymerase as well as thymidylate synthetase. a. Acyclovir b. Idoxuridine c. Podophyllotoxin d. Fomivirsen e. Imiquimod

Idoxuridine

A plant product used in the treatment of genital warts caused by DNA virus papilloma virus. a. Acyclovir b. Idoxuridine c. Podophyllotoxin d. Fomivirsen e. Imiquimod

Podophyllotoxin

This drug consists of 21 nucleotides and phosphothionate backbone. It is a DNA antisense molecule that blocks the translation of viral RNA and is used against retinal inflammation caused by CMV in AIDS patients. a. Acyclovir b. Idoxuridine c. Podophyllotoxin d. Fomivirsen e. Imiquimod

Fomivirsen

A nucleoside reverse transcriptase inhibitor which is an analogue of deoxythymidine where the 3’hydroxyl group is replaced by an azido group. a. Zidovudine b. Didanosine c. Lamivudine d. Abacavir e. Efavirenz

Zidovudine

The anti-HIV drug contains inosine as the nucleic acid base and is converted through a series of enzyme reaction to 2’,3’-dideoxyadenosine triphosphate which is the active drug. a. Zidovudine b. Didanosine c. Lamivudine d. Abacavir e. Efavirenz

Didanosine

Which of the following anti-HIV drug is an analogue of deoxycytidine where the 3’ carbon has been replaced by sulphur? a. Zidovudine b. Didanosine c. Lamivudine d. Abacavir e. Efavirenz

Lamivudine

The only guanosine analogue that is used against HIV infections and Hepatitis B. a. Zidovudine b. Didanosine c. Lamivudine d. Abacavir e. Efavirenz

Abacavir

A second generation non-nucleoside reverse transcriptase inhibitor that has a benzoxaxinone structure. a. Zidovudine b. Didanosine c. Lamivudine d. Abacavir e. Efavirenz

Efavirenz

Which of the following statements is/are correct regarding anti-HIV drugs? a. NRTIs are prodrugs that are converted by cellular enzymes to active triphosphates which act as enzyme inhibitors and chain terminators. b. NNRTIs act as enzyme inhibitors by binding to an allosteric binding site. c. PIs are designed to act as transition state inhibitors d. A and B only e. All of the above

All of the above

Below is the structure of chloramphenicol, a bacteriostatic agent that binds to the 50s subunit of ribosome. Which part of its structure is essential for drug activity? a. The nitro group b. The 2 alcohol groups c. The dichloroacetamide group d. A and B only e. All of the above

A and B