Description : The first amino acyl tRNA approaches 40 S ribosomal subunit in association with (A) eIF-1A and GTP (B) eIF-2 and GTP (C) eIF-2C and GTP (D) eIF-3 and GTP
Last Answer : Answer : B
Description : Eukaryotic initiation factors 4A, 4B and 4F bind to (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) mRNA (D) Amino acyl tRNA
Last Answer : Answer : C
Description : Peptidyl transferase activity is present in (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) eEF-2 (D) Amino acyl tRNA
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 : 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
Last Answer : Answer : A
Description : The newly entering amino acyl tRNA into A site requires (A) EF-II (B) Ribosomal RNA (C) mRNA (D) EF-I
Last Answer : Answer : D
Description : Binding of formylmehtionyl tRNA to 30 S ribosomal subunit of prokaryotes is inhibited by (A) Streptomycin (B) Chloramphenicol (C) Erythromycin (D) Mitomycin
Description : Initiation of protein synthesis begins with binding of (A) 40S ribosomal unit on mRNA (B) 60S ribosomal unit (C) Charging of tRNA with specific amino acid (D) Attachment of aminoacyl tRNA on mRNA
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 : Tetracylin prevents synthesis of polypeptide by (A) Blocking mRNA formation from DNA (B) Releasing peptides from mRNA-tRNA complex (C) Competing with mRNA for ribosomal binding sites (D) Preventing binding of aminoacyl 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.
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 eukaryotes, the 40 S pre-initiation complex contains all the following initiation factors except (A) eIF-1A (B) eIF-2 (C) eIF-3 (D) eIF-4
Description : In the process of elongation of chain binding of amino acyl tRNA to the A site requires (A) A proper codon recognition (B) GTP (C) EF-II (D) GDP
Description : What is the action of tetracycline in prokaryotes? A- It blocks translocation reaction on ribosomes B- It blocks peptidyltransferase reaction on ribosomes C- It blocks the binding of amino-acyl tRNA to the A site of ribosomes D- Not known with certainity
Last Answer : It blocks the binding of amino-acyl tRNA to the A site of ribosomes
Description : The primary mechanism underlying the resistance of gram-positive organisms to macrolide antibiotics is (a) Methylation of binding sites on the 50S ribosomal subunit (b) Formation of ... ) Formation of drug-inactivating acetyltranferases (e) Decreased drug permeability of the cytoplasmic membrane
Last Answer : Ans: A
Description : mRNA is complementary to the nucleotide sequence of (A) Coding strand (B) Ribosomal RNA (C) tRNA (D) Template strand
Description : Thymine is present in (A) tRNA (B) Ribosomal RNA (C) Mammalian mRNA(D) Prokaryotic mRNA
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 : 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 : 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
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 : The antibiotic which has a structure similar to the amino acyl end of tRNA tyrosine is (A) Actinomycin d (B) Streptomycin (C) Puromycin (D) Mitomycin c
Description : The first amino acyl tRNA which initiates translation in prokaryotes is (A) Mehtionyl tRNA (B) Formylmethionyl tRNA (C) Tyrosinyl tRNA (D) Alanyl tRNA
Description : The first amino acyl tRNA which initiates translation in eukaryotes is (A) Mehtionyl tRNA (B) Formylmethionyl tRNA (C) Tyrosinyl tRNA (D) Alanyl tRNA
Description : All the following statements about charging of tRNA are correct except (A) It is catalysed by amino acyl tRNA synthetase (B) ATP is converted into ADP and Pi in this reaction (C) The enzyme recognizes the tRNA and the amino acid (D) There is a separate enzyme for each tRNA
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 : eIF-4 B (A) Binds to 3’ chain initiation codon on mRNA (B) Binds to 3’ end of mRNA (C) Binds to 5’ end of mRNA (D) Unwinds mRNA near its 5’ end
Description : All the following statements about recognition of a codon on mRNA by an anticodon on tRNA are correct except (A) The recognition of the third base of the codon is not very precise (B) ... degeneracy of the genetic code (D) Wobble results in incorporation of incorrect amino acids in the protein
Description : All the following statements about tRNA are correct except (A) A given tRNA can be charged with only one particular amino acid (B) The amino acid is recognized by the anticodon of tRNA (C) The amino acid is attached to end of tRNA (D) The anticodon of tRNA finds the complementary codon on mRNA
Description : .The first phase of translation is (a) binding of mRNA to ribosome (b) recognition of DNA molecule (c) aminoacylation of tRNA (d) recognition of an anti-codon
Last Answer : (d) recognition of an anti-codon.
Description : The first phase of translation is (a) binding of mRNA to ribosome (b) recognition of DNA molecule (c) aminoacylation of tRNA (d) recognition of an anti-codon.
Last Answer : c) aminoacylation of tRNA
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 : 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 : 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 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 : Hormone receptors that stimulate cAMP production (A) are part of a complex of two proteins that transform the external signal into internal cAMP production (B) are proteins distinct and separate from those ... binding of the hormone (D) are not very specific and bind a number of different hormones
Description : The nucleotide binding site of G-proteins is present on their (A) α-Subunit (B) β-Subunit α- and β- (C) γ-Subunit (D) δ-Subunit
Description : Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein
Description : The RNA that pick up specific amino acid from amino acid pool in the cytoplasm to ribosome during protein synthesis is called (a) rRNA (b) RNA (c) mRNA (d) tRNA.
Last Answer : a) rRNA
Description : Amino acid sequence, in protein synthesis is decided by the sequence of (a) rRNA (b) tRNA (c) mRNA (d) cDNA.
Last Answer : (b) tRNA
Description : The RNA that pick up specific amino acid from amino acid pool in the cytoplasm to ribosome during protein synthesis is called (a) rRNA (b) RNA (c) mRNA (d) tRNA
Last Answer : tRNA
Description : .Amino acid sequence, in protein synthesis is decided by the sequence of (a) rRNA (b) tRNA (c) mRNA (d) cDNA.
Last Answer : (c) mRNA
Description : What happens at the ribosome in the production of a protein? a. mRNA brings the codon b. tRNA brings the anticodon c. the amino acids are linked by polypeptide bonds d. translation e. all the above
Last Answer : c. the amino acids are linked by polypeptide bonds
Description : During amino acid activation a(n) A-amino acid is bound to tRNA B- amino acid is bound to mRNA C-methyl group is attached to rRNA D-methyl group is attached to an amino acid
Last Answer : amino acid is bound to tRNA
Description : The interaction between the mRNA and tRNA determined the position of amino acid in a polypeptide sequence. This is called the A- stagerivity B- Wobble hypothesis C- Promiscuity D- adaptor hypothesis
Last Answer : adaptor hypothesis
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