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 : 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 a) Is a 23s rRNA b) forms peptide bonds c) component of ribosome d) all the three
Last Answer : d) all the three
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 : ATP is required for (A) Fusion of 40S and 60S of ribosome (B) Accommodation tRNA amino acid in a site of ribosome (C) Movement of ribosome along mRNA (D) formation of tRNA amino acid complex
Last Answer : Answer : D
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
Last Answer : Answer : A
Description : GTP is not required for (A) Capping L of mRNA (B) Fusion of 40S and 60S of ribosome (C) Accommodation of tRNA amino acid (D) Formation of tRNA amino acid complex
Description : During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.
Last Answer : (c) association of 30S mRNA with formyl-met- tRNA
Description : .During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.
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 : 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 : Elongation of a peptide chain involves all the following except (A) mRNA (B) GTP (C) Formyl-Met-tRNA (D) Tu, TS and G factors
Last Answer : Answer : C
Description : Erythromycin acts on ribosomes and inhibit (A) Formation of initiation complex (B) Binding of aminoacyl tRNA (C) Peptidyl transferase activity (D) Translocation
Description : The mRNA ready for protein synthesis has the ________ cap. (A) ATP (B) CTP (C) GTP (D) UTP
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 statement(s) is/are true concerning translation of the mRNA message to protein synthesis? a. An adaptor molecule, tRNA, recognizes specific nucleic acid bases and unites them ... and the free amino acid occurs in the free cytoplasm d. Complete protein synthesis takes hours
Last Answer : Answer: a, b The synthesis of protein involves conversion from a four-letter nucleotide language to one of 20 chemically distinct amino acids. This process is referred to as ... translation and be moving down the mRNA molecules simultaneously, thus increasing the rate of protein synthesis
Description : The following is required for the formation of coenyzme A: (A) ATP (B) GTP (C) CTP (D) None of these
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
Description : Peptidyl transferase activity of 50 S ribosomal subunits is inhibited by (A) Rifampicin (B) Cycloheximide (C) Chloramphenicol (D) Erythromycin
Description : Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein
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 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 : The enzyme amino acyl tRNA synthetase is involved in (A) Dissociation of discharged tRNA from 80S ribosome (B) Charging of tRNA with specific amino acids (C) Termination of protein synthesis (D) Nucleophilic attack on esterified carboxyl group of peptidyl tRNA
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 : The nucleophilic attack on the esterified carboxyl group of the peptidyl-tRNA occupying the P site and the α-amino group of the new amino acyl tRNA, the number of ATP required by the amino acid on the charged tRNA is (A) Zero (B) One (C) Two (D) Four
Description : The maximum formation of mRNA occurs in (a) ribosome (b) nucleoplasm (c) cytoplasm (d) nucleolus.
Last Answer : (b) nucleoplasm
Last Answer : (d) nucleolus.
Description : The formation of a peptide bond during the elongation step of protein synthesis results in the splitting of how many high energy bonds? (A) 1 (B) 2 (C) 3 (D) 4
Description : From two amino acids peptide bond formation involves removal of one molecule of (A) Water (B) Ammonia (C) Carbondioxide (D) Carboxylic acid
Description : A growing peptide in a ribosome can not be shifted to the adjacent ribosome because (A) It is firmly attached (B) It will get the amino acid cleaved (C) The gap between the ribosomes is too big for a shift (D) The adjacent ribosomes have different composition
Description : In the biosynthesis of c-DNA, the joining enzyme ligase requires (A) GTP (B) ATP (C) CTP (D) UTP
Description : Synthesis of GMP and IMP requires the following: (A) NH3 NAD+, ATP (B) Glutamine, NAD+, ATP (C) NH3, GTP, NADP+ (D) Glutamine, GTP, NADP+
Description : For unwinding of double helical DNA, (A) Energy is provided by ATP (B) Energy is provided by GTP (C) Energy can be provided by either ATP or GTP (D) No energy is required
Description : Initiation of protein synthesis requires (A) ATP (B) AMP (C) GDP (D) GTP
Description : UDP and UTP are formed by phosphorylation from (A) AMP (B) ADP (C) ATP (D) GTP
Description : The cofactors required for synthesis of adenylosuccinate are (A) ATP, Mg++ (B) ADP (C) GTP, Mg++ (D) GDP
Description : The most abundant free nucleotide in mammalian cells is (A) ATP (B) NAD (C) GTP (D) FAD
Description : G-proteins have a nucleotide binding site for (A) ADP/ATP (B) GDP/GTP (C) CDP/CTP (D) UDP/UTP
Description : Coenzyme for phosphoenolpyruvate carboxykinase is (A) ATP (B) ADP (C) GTP (D) GDP
Description : The enzyme phosphoenolpyruvate carboxykinase catalyses the conversion of oxaloacetate to phosphoenolpyruvate requires (A) ATP (B) ADP (C) AMP (D) GTP
Description : In the reaction below, Nu TP stands for NuTP + glucose → Glucose 6–Phosphate + NuDP. (A) ATP (B) CTP (C) GTP (D) UTP
Description : The enzyme acyl-CoA synthase catalyses the conversion of a fatty acid of an active fatty acid in the presence of (A) AMP (B) ADP (C) ATP (D) GTP
Description : The 2 energy rich compounds needed for protein biosynthesis are (A) ATP and GTP (B) ATP and UTP (C) ATP and CTP (D) ATP and TTP
Description : For biosynthesis of proteins (A) Amino acids only are required (B) Amino acids and nucleic acids only are required (C) Amino acid, nucleic acids and ATP only are required (D) Amino acids, nucleic acids, ATP, GTP, enzymes and activators are required
Description : Allsoteric activator of glutamate dehydrogenase is (A) ATP (B) GTP (C) ADP and GDP (D) AMP and GMP
Description : UDP-Glucose is converted to UDPGlucuronic acid by (A) ATP (B) GTP (C) NADP+ (D) NAD+
Last Answer : B
Description : The function of a repressor protein in an operon system is to prevent synthesis by binding to (A) The ribosome (B) A specific region of the operon preventing transcription of structural genes (C) The RNA polymerase (D) A specific region of the mRNA preventing translation to protein
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