51-100 Flashcards
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
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
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
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
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
R2
A sulphonamide used in combination with pyrimethamine in the treatment of Malaria.
a. Sulfadiazine
b. Sulfathiazole
c. Sulfadoxine
d. Sulfamethoxazole
e. Sulfones
Sulfadoxine
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
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
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
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
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
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
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
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
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
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.
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
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
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
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
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
