That sulfonamides act by inhibiting folate synthesis
in bacteria is supported by the following findings
except:
A. Paraaminobenzoic acid antagonises the
action of sulfonamides
B. Methionine antagonises the action of sulfonamides
C. Purines and thymidine present in pus antagonise the action of sulfonamides
D. Bacteria that utilise folic acid taken up
from the medium are insensitive to sulfonamides

1 Answer

Answer :

B. Methionine antagonises the action of sulfonamides

Related questions

Description : The sulfonamides interfere with bacterial metabolism by a. blocking cell wall synthesis. b. disrupting folic acid metabolism. c. reacting with bacterial cell membranes. d. inhibiting DNA replication.

Last Answer : b. disrupting folic acid metabolism.

Description : Gram negative organisms are largely insensitive to benzyl penicillin because: A. They produce large quantities of penicillinase B. They do not utilise D-alanine whose incorporation in the cell wall is inhibited ... multilayer cell wall of gram negative bacteria D. Both A' and B' are correct

Last Answer : . Benzyl penicillin is not able to penetrate deeper into the lipoprotein-peptidoglycan multilayer cell wall of gram negative bacteria

Description : The metabolic reaction requiring vitamin B12 but not folate is: A. Conversion of malonic acid to succinic acid B. Conversion of homocysteine to methionine C. Conversion of serine to glycine D. Thymidylate synthesis

Last Answer : A. Conversion of malonic acid to succinic acid

Description : Ethanol is used in methanol poisoning because it: A. Antagonises the actions of methanol B. Stimulates the metabolism of methanol and reduces its blood level C. Inhibits the metabolism of methanol and generation of toxic metabolite D. Replenishes the folate stores depleted by methano

Last Answer : C. Inhibits the metabolism of methanol and generation of toxic metabolite

Description : Trimethoprim and sulfamethoxazole are examples of synthesis. a. Sulfonamides; PABA b. Penicillins; Cell Wall c. Sulfonamides; Folic Acid d. Macrolides; Protein

Last Answer : c. Sulfonamides; Folic Acid

Description : The following is true of vancomycin except: A. It is a bactericidal antibiotic active primarily against gram positive bacteria B. It acts by inhibiting bacterial protein synthesis C. It is an alternative to penicillin for enterococcal endocarditis D. It can cause deafness as a dose related toxicity

Last Answer : B. It acts by inhibiting bacterial protein synthesis

Description : A patient of megaloblastic anaemia was treated with oral folic acid 5 mg daily. After 2 weeks he reported back with cognitive deficit, sensory disturbance, depressed knee jerk, while ... therapy has unmasked pyridoxine deficiency D. Patient has folate reductase abnormality in the nervous system

Last Answer : D. Patient has folate reductase abnormality in the nervous system

Description : The following is true of sulfonamides except: A. They are more likely to produce crystalluria in alkaline urine in which they are less soluble B. They are primarily metabolized by acetylation ... in the urinary tract D. Used alone, they have become therapeutically unreliable for serious infections

Last Answer : A. They are more likely to produce crystalluria in alkaline urine in which they are less soluble

Description : The characteristic feature(s) of penicillin G is/are: A. It is unstable in aqueous solution B. Its antibacterial action is unaffected by pus and tissue fluids C. It is equally active against resting and multiplying bacteria D. Both ‘A’ and ‘B’ are correc

Last Answer : D. Both ‘A’ and ‘B’ are correct

Description : Methotrexate blocks the synthesis of thymidine monophosphate by inhibiting the activity of the enzyme: (A) Dihydrofolate reductase (B) Orotate phosphoribosyl transferase (C) Ribonucleotide reductase (D) Dihydroorotase

Last Answer : Answer : A

Description : Select the drug that antagonises diazepam action noncompetitively: A. Adenosine B. Flumazenil C. Bicuculline D. Valproic acid

Last Answer : C. Bicuculline

Description : Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following ... are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Last Answer : Answer: a, b, d Penicillins, cephalosporins, and monobactams possess a b-lactam ring of some type and act to bind bacterial division plate proteins, thus inhibiting cell wall ... act in different mechanisms to inhibit protein synthesis, therefore two agents in combination act synergistically

Description : The polyene antibiotics act by: A. Inhibiting fungal cytochrome P450 enzyme B. Binding to ergosterol and creating micropores in fungal cell membrane C. Inhibiting fungal DNA synthesis D. Disorienting microtubules in fungal cells

Last Answer : B. Binding to ergosterol and creating micropores in fungal cell membrane

Description : Piperazine antagonises the anthelmintic action of the following drug: A. Pyrantel pamoate B. Mebendazole C. Albendazole D. Niclosamide

Last Answer : A. Pyrantel pamoate

Description : Choose the correct statement about amiloride: A. It antagonises the action of aldosterone B. It can be used to treat lithium induced diabetes insipidus C. It increases calcium loss in urine D. It is dose to dose less potent than triamterene

Last Answer : B. It can be used to treat lithium induced diabetes insipidus

Description : Nalorphine is nearly equipotent analgesic as morphine, but is not used clinically as an analgesic because: A. It causes more marked respiratory depression B. It has higher abuse potential C. It antagonises the action of morphine D. It produces prominent dysphoric effects

Last Answer : D. It produces prominent dysphoric effects

Description : Features of µ (Mu) opioid receptor include the following except: A. Acts by inhibiting cAMP formation B. Mediates miotic action C. Mediates low ceiling respiratory depression D. Mediates high ceiling supraspinal analgesia

Last Answer : C. Mediates low ceiling respiratory depression

Description : Penicillins interfere with bacterial cell wall synthesis by: A. Inhibiting synthesis of N-acetyl muramic acid pentapeptide B. Inhibiting conjugation between N-acetyl muramic acid and N-acetyl ... cross link the peptidoglycan residues D. Counterfeiting for D-alanine in the bacterial cell wall

Last Answer : C. Inhibiting transpeptidases and carboxypeptidases which cross link the peptidoglycan residues

Description : The antiviral action of amantadine is exerted through: A. Interaction with the viral M2 protein B. Interaction with a virus directed thymidine kinase C. Inhibition of a viral protease enzyme D. Inhibition of viral RNA mediated DNA synthesi

Last Answer : A. Interaction with the viral M2 protein

Description : Folic acid or folate consists of the (A) Base pteridine, p-amino benzoic acid and asparate (B) Base purine, p-amino benzoic acid and glutamate (C) Base pteridine, p-amino benzoic acid and glutamate (D) Base purine, p-hydroxy benzoic acid and glutamate

Last Answer : Answer : C

Description : Trimethoprim inhibits bacteria without affecting mammalian cells because: A. It does not penetrate mammalian cells B. It has high affinity for bacterial but low affinity for mammalian dihydrofolate ... bacterial folate synthetase as well as dihydrofolate reductase enzymes D. All of the above

Last Answer : B. It has high affinity for bacterial but low affinity for mammalian dihydrofolate reductase enzyme

Description : Methotrexate has the following attributes except: A. It is cell cycle specific and kills cells in the S phase B. Its toxicity primarily affects bone marrow and epithelial structures C. Folic acid reverses its toxic effects D. It is the drug of choice for choriocarcinoma

Last Answer : C. Folic acid reverses its toxic effects

Description : Features of methylcobalamin include the following: A. It is an active coenzyme form of vit B12 B. It is required for the synthesis of S-adenosyl methionine C. It is specifically indicated for correcting neurological defects of vit B12 deficiency D. All of the above

Last Answer : D. All of the above

Description : Vinca alkaloids exert antitumor activity by: A. Activating topoisomerase II to cause breaks in DNA strands B. Crosslinking DNA strands C. Inhibiting DNA mediated RNA synthesis D. Inhibiting polymerization of tubulin to form intracellular microtubules

Last Answer : D. Inhibiting polymerization of tubulin to form intracellular microtubules

Description : Rifampin kills tubercle bacilli by: A. Binding to mycobacterial DNA dependent RNA polymerase B. Inhibiting mycobacterial DNA synthesis C. Inhibiting synthesis of mycolic acids in mycobacteria D. Damaging mycobacterial mitochondria

Last Answer : A. Binding to mycobacterial DNA dependent RNA polymerase

Description : What is true of Quinupristin-Dalfopristin: A. It is a synergistic combination of two similar antibiotics B. It acts by inhibiting bacterial protein synthesis C. It is active against most resistant coccal infections D. All of the above are correct

Last Answer : D. All of the above are correct

Description : Chloramphenicol inhibits bacterial protein synthesis by: A. Binding to 30S ribosome and inhibiting attachment of aminoacyl tRNA B. Binding to 50S ribosome and preventing peptide bond formation C. Binding to ... chain D. Binding to both 30S and 50S ribosome and inducing misreading of mRNA code

Last Answer : B. Binding to 50S ribosome and preventing peptide bond formation

Description : Aspirin prolongs bleeding time by inhibiting the synthesis of: A. Clotting factors in liver B. Prostacyclin in vascular endothelium C. Cyclic AMP in platelets D. Thromboxane A2 in platelets

Last Answer : D. Thromboxane A2 in platelets

Description : Carbimazole acts by inhibiting: A. Iodide trapping B. Oxidation of iodide C. Proteolysis of thyroglobulin D. Synthesis of thyroglobulin protein

Last Answer : B. Oxidation of iodide

Description : Low doses of aspirin prolong bleeding time by selectively inhibiting synthesis of the following mediator in the platelets: A. Thromboxane A2 B. 5-Hydroxytryptamine C. Platelet activating factor D. Prostacyclin

Last Answer : A. Thromboxane

Description : Both folic acid and methyl cobalamin (vitamin B12) are required in (A) Deamination of serine (B) Deamination of threonine (C) Conversion of pyridoxal phosphate to pyridoxamine phosphate (D) Methylation of homocystein to methionine

Last Answer : Answer : D

Description : All the following statements about primary gout are true except (A) Its inheritance is X-linked recessive (B) It can be due to increased activity of PRPP synthetase (C) It can be ... activity of hypoxanthine guanine phosphoribosyl transferase (D) De novo synthesis of purines is increased in it

Last Answer : Answer : C

Description : Carbon 6-of purine skeleton comes from (A) Atmospheric CO2 (B) 1 carbon carried by folate (C) Betoine (D) Methionine

Last Answer : Answer : A

Description : The mode of action of polymyxin is to A- inhibit protein synthesis B- inhibit DNA synthesis C- injury to the plasma membrane D- inhibit folic acid synthesis

Last Answer : injury to the plasma membrane

Description : Aminoglycoside antibiotics exert the following action(s) on sensitive bacteria: A. Induce synthesis of defective proteins B. Make bacterial cell membrane more leaky C. Augment their own carrier mediated entry into the bacteria D. All of the above

Last Answer : D. All of the above

Description : The most important mechanism by which tetracycline antibiotics exert antimicrobial action is: A. They chelate Ca2+ ions and alter permeability of bacterial cell membrane B. They bind to 30S ribosomes ... peptide chain in the bacteria D. They interfere with DNA mediated RNA synthesis in bacteria

Last Answer : B. They bind to 30S ribosomes and inhibit bacterial protein synthesis

Description : The following is true of bupropion except: A. It inhibits dopamine reuptake along with inhibiting noradrenaline reuptake B. It produces sedation as a side effect C. It is being used as an aid for smoking cessation D. It is likely to produce seizures in overdose

Last Answer : B. It produces sedation as a side effect

Description : The following is true about entacapone except: A. It acts by inhibiting degradation of dopamine in the brain B. If prolongs the therapeutic effect of levodopacarbidopa in parkinsonism C. It can accentuate levodopa induced dyskinesias D. It can cause diarrhoea as a side effec

Last Answer : A. It acts by inhibiting degradation of dopamine in the brain

Description : Adrenaline raises blood glucose level by the following actions except: A. Inducing hepatic glycogenolysis B. Inhibiting insulin secretion from pancreatic β cells C. Augmenting glucagon secretion from pancreatic α cells D. Inhibiting peripheral glucose utilization

Last Answer : D. Inhibiting peripheral glucose utilization

Description : Adrenaline raises blood glucose level by the following actions except: A. Inducing hepatic glycogenolysis B. Inhibiting insulin secretion from pancreatic β cells C. Augmenting glucagon secretion from pancreatic α cells D. Inhibiting peripheral glucose utilization

Last Answer : D. Inhibiting peripheral glucose utilization

Description : Leishmania donovani is susceptible to certain antifungal drugs because both fungi and Leishmania: A. Utilise purine salvage pathway B. Utilise similar glycolytic mechanisms C. Have similar topoisomerase II enzyme D. Have ergosterol in their cell membranes

Last Answer : D. Have ergosterol in their cell membranes

Description : Thiazide diuretics enhance K+ elimination in urine primarily by: A. Inhibiting proximal tubular K+ reabsorption B. Inhibiting Na+ K+-2Cl- cotransport in the ascending limb of loop of Henle C ... in the distal tubular fluid to exchange with interstitial K+ D. Potentiating the action of aldosterone

Last Answer : C. Increasing the availability of Na+ in the distal tubular fluid to exchange with interstitial K

Description : Dantrolene sodium reduces skeletal muscle tone by: A. Reducing acetylcholine release from motor nerve endings B. Suppressing spinal polysynaptic reflexes C. Inhibiting the generation of muscle action potential D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre

Last Answer : D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre

Description : Corticosteroids exert antiinflammatory action by inhibiting the following enzyme: A. Cyclooxygenase B. Lipoxygenase C. Phospholipase-A D. Phosphodiesterase

Last Answer : C. Phospholipase-A

Description : Which of the following is not likely to be the cause of failure of antimicrobial therapy of an acute infection: A. Improper selection of drug and dose B. Acquisition of resistance during treatment C. Failure to drain the pus D. Uncontrolled diabetes mellitus

Last Answer : B. Acquisition of resistance during treatment

Description : An example of feedback inhibition is (A) Allosteric inhibition of hexokinase by glucose6-phosphate (B) Cyanide action on cytochrome (C) Sulpha drug on folic acid synthesizer bacteria (D) Reaction between succinic dehydrogenase and succinic acid

Last Answer : Answer : A

Description : Choose the correct statement(s) about retroviral protease inhibitors: A. They act at an early step in HIV replication B. They are more active in inhibiting HIV than zidovudine C. They inhibit CYP3A4 and interact with many other drugs D. Both 'B' and 'C' are correct

Last Answer : D. Both 'B' and 'C' are correct

Description : Indicate the attribute that is common to both polymyxin B and bacitracin: A. Both are active against gram negative bacteria B. Both are too toxic for systemic use C. Both act by inhibiting bacterial cell wall synthesis D. Both a

Last Answer : B. Both are too toxic for systemic use

Description : The most likely explanation of differing sensitivities of different bacteria to various penicillins is: A. Differing susceptibilities of the various penicillins to β-lactamases produced by different ... into different bacteria D. Differing rates of cell wall synthesis by different bacteria

Last Answer : B. Differing affinities of penicillin binding proteins present in different bacteria towards various penicillins

Description : In inherited deficiency of hypoxanthine guanine phosphoribosyl transferase (A) De novo synthesis of purine nucleotides is decreased (B) Salvage of purines is decreased (C) Salvage of purines is increased (D) Synthesis of uric acid is decreased

Last Answer : Answer : B