Description : Erythromycin binds to 50 S ribosomal sub unit and (A) Inhibits binding of amino acyl tRNA (B) Inhibits Peptidyl transferase activity (C) Inhibits translocation (D) Causes premature chain termination
Last Answer : Answer : C
Description : Binding of formylmehtionyl tRNA to 30 S ribosomal subunit of prokaryotes is inhibited by (A) Streptomycin (B) Chloramphenicol (C) Erythromycin (D) Mitomycin
Last Answer : Answer : A
Description : Peptidyl transferase activity is present in (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) eEF-2 (D) Amino acyl tRNA
Last Answer : Answer : B
Description : Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein
Description : Mitochondrial protein synthesis is inhibited by (A) Cycloheximide (B) Chloramphenicol (C) Diptheria toxin (D) None of these
Description : In prokaryotes, chloramphenicol (A) Causes premature release of the polypeptide chain (B) Causes misreading of the mRNA (C) Depolymerises DNA (D) Inhibits peptidyl transferase activity
Description : Erythromycin acts on ribosomes and inhibit (A) Formation of initiation complex (B) Binding of aminoacyl tRNA (C) Peptidyl transferase activity (D) Translocation
Last Answer : Answer : D
Description : Which of the following concerning the conjugation of bilirubin is correct? 1) is catalysed by a glucuronyl transferase 2) occurs in the Kupfer cells of the liver 3) is increased by valproate 4) is inhibited by rifampicin 5) is impaired in Dubin-Johnson syndrome
Last Answer : Answers-1 b - Hepatocytes. c - Enzyme inhibitor. d - Enzyme inducer. e - Conjugation is OK but excretion from the hepatocyte into the bile is impaired. (Gilbert's syndrome ... bilirubinaemia. Dubin-Johnson syndrome - bilirubin can't Depart from the hepatocyte - conjugated bilirubinaemia.)
Description : Select the antibiotic which inhibits bacterial protein synthesis by interfering with translocation of elongating peptide chain from acceptor site back to the peptidyl site of the ribosome so that ... chain is prematurely terminated: A. Chloramphenicol B. Erythromycin C. Tetracycline D. Streptomycin
Last Answer : B. Erythromycin
Description : The most important mechanism by which gram negative bacilli acquire chloramphenicol resistance is (a) Decreased permeability into the bacterial cell (b) Acquisition of a plasmid encoded ... bacterial ribosome for chloramphenicol (d) Switching over from ribosomal to mitochondrial protein synthesis
Last Answer : Ans: B
Description : The most important mechanism by which gram negative bacilli acquire chloramphenicol resistance is: A. Decreased permeability into the bacterial cell B. Acquisition of a plasmid encoded ... the bacterial ribosome for chloramphenicol D. Switching over from ribosomal to mitochondrial protein synthesi
Last Answer : B. Acquisition of a plasmid encoded for chloramphenicol acetyl transferas
Description : Tetracyclines inhibit binding of amino acyl tRNAs to (A) 30 S ribosomal subunits (B) 40 S ribosomal subunits (C) 50 S ribosomal subunits (D) 60 S ribosomal subunits
Description : In prokaryotes, the ribosomal subunits are (A) 30 S and 40 S (B) 40 S and 50 S (C) 30 S and 50 S (D) 40 S and 60 S
Description : Streptomycin prevents synthesis of polypeptide by (A) Inhibiting initiation process (B) Releasing premature polypeptide (C) Inhibiting peptidyl transferase activity (D) Inhibiting translocation
Description : The mechanism of antibacterial action of tetracycline involves (a) Binding to a component of the 50S ribosomal subunit (b) Inhibition of translocase activity (c) Blockade of binding of ... (d) Selective inhibition of ribosomal peptidyl transferases (e) Inhibition of DNA-dependent RNA polymerase
Last Answer : Ans: C
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 : Ribozymes are (A) Enzymes present in ribosomes (B) Enzymes which combine the ribosomal subunits (C) Enzymes which dissociate (D) Enzymes made up of RNA
Description : After formation of a peptide bond, mRNA is translocated along the ribosome by (A) eEF-1 and GTP (B) eEF-2 and GTP (C) Peptidyl transferase and GTP (D) Peptidyl transferase and ATP
Description : Translocation of the newly formed peptidyl tRNA at the A site into the empty P site involves (A) EF-II, GTP (B) EF-I, GTP (C) EF-I, GDP (D) Peptidyl transferase, GTP
Description : The α-amino group of the new amino acyl tRNA in the A site carries out a nucleophilic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) DNA ligase
Description : Which of the following drugs can precipitate hypoglycaemia if given to a diabetic controlled with a sulfonylurea drug: A. Phenobarbitone B. Chloramphenicol C. Rifampicin D. Oral contraceptive
Last Answer : . Chloramphenicol
Description : Purine biosynthesis is inhibited by (A) Aminopterin (B) Tetracyclin (C) Methotrexate (D) Chloramphenicol
Description : Which of the following step of translation does not consume a high energy phosphate bond? (a) Peptidyl transferase reaction (b) Aminoacyl tRNA binding to A-site (c) Translocation (d) Amino acid activation
Last Answer : (b) Aminoacyl tRNA binding to A-site
Last Answer : (a) Peptidyl transferase reaction
Description : Which of the following molecule catalyzes the transpeptidation reaction? A.RNA polymerase B.Peptidyl transferase C.DNA ligase D.DNA polymerase
Last Answer : B.Peptidyl transferase
Description : Peptidyl transferase a) Is a 23s rRNA b) forms peptide bonds c) component of ribosome d) all the three
Last Answer : d) all the three
Description : Which binding is inhibited by pactamycin? A- Aminoacyl-tRNA to the A-site of 30S subunit B- Initiator-tRNA to 30S/40S initiation complexes C- Peptidyl t-RNA to the 50S subunit D- Formation of peptide bond in P site
Last Answer : Initiator-tRNA to 30S/40S initiation complexes
Description : Bacteria become erythromycin resistant by the following mechanisms except: A. Becoming less permeable to erythromycin B. Elaborating an erythromycin esterase enzyme C. Elaborating a protection ... the erythromycin binding site D. Altering the ribosomal binding site through a methylase enzyme
Last Answer : C. Elaborating a ‘protection protein’ which blocks the erythromycin binding site
Description : Which out of the following antibiotics penetrates blood-CSF barrier the best (a) Erythromycin (b) Gentamicin (c) Tetracycline (d) Chloramphenicol
Last Answer : Ans: D
Description : An 8-year-old child presented with brownish discoloured and deformed anterior teeth. History of having received an antibiotic about 4 years earlier was obtained. Which antibiotic could be responsible for the condition ? (a) Chloramphenicol (b) Tetracycline (c) Erythromycin (d) Genetamicin
Description : Select the antibiotic whose dose must be reduced in patients with renal insufficiency (a) Ampicillin (b) Chloramphenicol (c) Tobramycin (d) Erythromycin
Description : Two drugs that affect cell wall synthesis are a. Erythromycin and penicillin. b. Vancomycin and cephalosporin. c. Tetracycline and polymyxin b. d. Chloramphenicol and streptomycin.
Last Answer : a. Erythromycin and penicillin.
Description : A premature neonate suffered respiratory distress and was given an antibiotic 100 mg/kg/day orally. Over the next two days his condition worsened, he become dull, stopped feeding, developed ... most likely antibiotic given to him: A. Ampicillin B. Chloramphenicol C. Erythromycin D. Ciprofloxacin
Last Answer : B. Chloramphenico
Description : The following antibiotic penetrates blood-CSF barrier the best: A. Erythromycin B. Gentamicin C. Tetracycline D. Chloramphenicol
Last Answer : D. Chloramphenicol
Description : An 8-year-old child presented with brownish discoloured and deformed anterior teeth. History of having received an antibiotic about 4 years earlier was obtained. Which antibiotic could be responsible for the condition: A. Chloramphenicol B. Tetracycline C. Erythromycin D. Gentamicin
Last Answer : Tetracycline
Description : Select the antibiotic whose dose must be reduced in patients with renal insufficiency: A. Ampicillin B. Chloramphenicol C. Tobramycin D. Erythromycin
Last Answer : C. Tobramycin
Description : 2 Which antibiotic is primarily bacteriostatic but becomes bactericidal at higher concentrations: A. Erythromycin B. Tetracycline C. Chloramphenicol D. Ampicillin
Last Answer : A. Erythromycin Although erythromycin is primarily bacteriostatic, it is bactericidal at high concentrations for some Gram-positive species, such as group A streptococci and pneumococci
Description : The following antibiotic accentuates the nuromuscular blockade produced by pancuronium: A. Streptomycin B. Erythromycin C. Penicillin G D. Chloramphenicol
Last Answer : A. Streptomycin
Description : Gary baby syndrome occur in new born with a) Tetracycline b) Chloramphenicol c) Penicillin d) Erythromycin
Last Answer : b) Chloramphenicol
Description : The shape of an enzyme and consequently its activity can be reversibly altered from moment to moment by (A) Heat (B) Amino acid substrate (C) Allosteric subunits (D) Sulfur substitutions
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
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
Description : Insulin regulates fatty acid synthesis by (A) Dephosphorylating of acetyl CoA carboxylase (B) Activating phosphorylase (C) Inhibiting malonyl CoA formation (D) Controlling carnitine-Acyl CoA transferase activity
Description : Ceruloplasmin shows the activity (A) As ferroxidase (B) As reductase (C) As ligase (D) As transferase
Description : A deficiency of copper effects the formation of normal collagen by reducing the activity of which of the following enzyme? (A) Prolyl hydroxylase (B) Lysyl oxidase (C) Lysyl hydroxylase (D) Glucosyl transferase
Description : Increased serum ornithine carabamoyl transferase activity is diagnostic of (A) Myocardial infarction (B) Hemolytic jaundice (C) Bone disease (D) Acute viral hepatitis
Description : Activity of cytochrome oxidase is inhibited by (A) Sulphite (B) Sulphate (C) Arsenite (D) Cyanide
Description : The activity of HMG-CoA reductase is inhibited by (A) A fungal inhibitor mevastatin (B) Probucol (C) Nicotinic acid (D) Clofibrate
Description : Pyruvate dehydrogenase activity is inhibited by (A) Mercury (B) Zinc (C) Calcium (D) Sodium
Description : All of the following statements about the enzymic complex that carries out the synthesis of ATP during oxidative phosphorylation are correct except (A) It is located on the matrix side of the inner ... inhibited by oligomycin (C) It can exhibit ATPase activity (D) It can bind molecular O2
Last Answer : D