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

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
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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 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

Last Answer : Answer : C

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 : 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

Last Answer : Answer : B

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 : 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

Peptidyl transferase activity is present in (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) eEF-2 (D) Amino acyl tRNA

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

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 : 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

Last Answer : Answer : B

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 : 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

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

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

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

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 : (a) Peptidyl transferase reaction

A molecule of CO2 is captured by biotin when it acts as coenzyme for carboxylation reaction. The carboxyl group is covalently attached to (A) A nitrogen (N1) of the biotin molecule (B) Sulphur of thiophene ring (C) α-Amino group of lysine (D) α-Amino group of protein

Description : A molecule of CO2 is captured by biotin when it acts as coenzyme for carboxylation reaction. The carboxyl group is covalently attached to (A) A nitrogen (N1) of the biotin molecule (B) Sulphur of thiophene ring (C) α-Amino group of lysine (D) α-Amino group of protein

Last Answer : Answer : A

In biotin-containing enzymes, the biotin is bound to the enzyme by (A) An amide linkage to carboxyl group of glutamine (B) A covalent bond with CO2 (C) An amide linkage to an amino group of lysine (D) An amide linkage to α-carboxyl group of protein

Description : In biotin-containing enzymes, the biotin is bound to the enzyme by (A) An amide linkage to carboxyl group of glutamine (B) A covalent bond with CO2 (C) An amide linkage to an amino group of lysine (D) An amide linkage to α-carboxyl group of protein

Last Answer : Answer : C

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 : 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

The newly entering amino acyl tRNA into A site requires (A) EF-II (B) Ribosomal RNA (C) mRNA (D) EF-I

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

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 : 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

Last Answer : Answer : A

Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein

Description : Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein

Last Answer : Answer : C

eIF-1A and eIF-3 are required (A) For binding of amino acyl tRNA to 40 S ribosomal subunit (B) For binding of mRNA to 40 S ribosomal subunit (C) For binding of 60 S subunit to 40 S subunit (D) To prevent binding of 60 S subunit to 40 S subunit

Description : eIF-1A and eIF-3 are required (A) For binding of amino acyl tRNA to 40 S ribosomal subunit (B) For binding of mRNA to 40 S ribosomal subunit (C) For binding of 60 S subunit to 40 S subunit (D) To prevent binding of 60 S subunit to 40 S subunit

Last Answer : Answer : D

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

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

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

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

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

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

Arrange the following carboxyl compounds in increasing order of their reactivity in nucleophilic addition reactions. Explain with proper reasoning : Benzaldehyde. p-tolualdeyde, p-nitrobenzaldehyde, Acetophenone.

Description : Arrange the following carboxyl compounds in increasing order of their reactivity in nucleophilic addition reactions. Explain with proper reasoning : Benzaldehyde. p-tolualdeyde, p-nitrobenzaldehyde, Acetophenone.

Last Answer : Ans. Acetophenone is a ketone while all others are aldehydes, therefore it is least reactive. In p-tolualdehyde, there is methyl group (CH3 ) at para position w.r.t. to the ... overall order of increasing reactivity : acetophenone < p-tolualdehyde < benzaldehyde < p-nitrobenzaldehyde. 

Acyl-CoA dehydrogenase converts Acyl CoA to α-β unsaturated acyl-CoA in presence of the coenzyme: (A) NAD+ (B) NADP+ (C) ATP (D) FAD

Description : Acyl-CoA dehydrogenase converts Acyl CoA to α-β unsaturated acyl-CoA in presence of the coenzyme: (A) NAD+ (B) NADP+ (C) ATP (D) FAD

Last Answer : Answer : D

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 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

Last Answer : Answer : C

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

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

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

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

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 prokaryotes is (A) Mehtionyl tRNA (B) Formylmethionyl tRNA (C) Tyrosinyl tRNA (D) Alanyl tRNA

Last Answer : Answer : B

The first amino acyl tRNA which initiates translation in eukaryotes 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

Last Answer : Answer : A

The active site of an enzyme is formed by a few of the enzymes: (A) R groups of the amino acids (B) Amino groups of the amino acids (C) Carboxyl group of the amino acids (D) Exposed sulfur bonds

Description : The active site of an enzyme is formed by a few of the enzymes: (A) R groups of the amino acids (B) Amino groups of the amino acids (C) Carboxyl group of the amino acids (D) Exposed sulfur bonds

Last Answer : Answer : C

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 : 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

Last Answer : Answer : B

Erythromycin acts on ribosomes and inhibit (A) Formation of initiation complex (B) Binding of aminoacyl tRNA (C) Peptidyl transferase activity (D) Translocation

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

Esters and amides are most easily made by nucleophilic acyl substitution reactions on : (a) acid anhydrides (b) carboxylates (c) carboxylic acids (d) acid chlorides

Description : Esters and amides are most easily made by nucleophilic acyl substitution reactions on : (a) acid anhydrides (b) carboxylates (c) carboxylic acids (d) acid chlorides

Last Answer : acid chlorides

The central heavy metal cobalt of vitamin B12 is coordinately bound to (A) Cyanide group (B) Amino group (C) Carboxyl group (D) Sulphide group

Description : The central heavy metal cobalt of vitamin B12 is coordinately bound to (A) Cyanide group (B) Amino group (C) Carboxyl group (D) Sulphide group

Last Answer : Answer : A

What is the name given to the bond that links an amino group of one molecule of an amino acid to a carboxyl group of another amino acid?

Description : What is the name given to the bond that links an amino group of one molecule of an amino acid to a carboxyl group of another amino acid?

Last Answer : ANSWER: PEPTIDE LINK or AMIDE LINK or PEPTIDE BOND 

The greater acidity of carboxylic acids compared to alcohols arises primarily from : (a) the electron-donating effect of the hydroxyl group (b) the electron-withdrawing effect of the carboxyl oxygen (c) the acidity of α-hydrogens of carboxylic acids (d) the resonance stability associated with the carboxylate ion

Description : The greater acidity of carboxylic acids compared to alcohols arises primarily from : (a) the electron-donating effect of the hydroxyl group (b) the electron-withdrawing effect of the carboxyl ... of α-hydrogens of carboxylic acids (d) the resonance stability associated with the carboxylate ion

Last Answer : the resonance stability associated with the carboxylate ion

α-Oxidation i.e., the removal of one carbon at a time from the carboxyl end of the molecule has been detected in (A) Brain tissue (B) Liver (C) Adipose tissue (D) Intestine

Description : α-Oxidation i.e., the removal of one carbon at a time from the carboxyl end of the molecule has been detected in (A) Brain tissue (B) Liver (C) Adipose tissue (D) Intestine

Last Answer : Answer : A

In synthesis of Triglyceride from α-Glycero phosphate and acetyl CoA, the first intermediate formed is (A) β-diacyl glycerol (B) Acyl carnitine (C) Monoacyl glycerol(D) Phosphatidic acid

Description : In synthesis of Triglyceride from α-Glycero phosphate and acetyl CoA, the first intermediate formed is (A) β-diacyl glycerol (B) Acyl carnitine (C) Monoacyl glycerol(D) Phosphatidic acid

Last Answer : Answer : D

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 : 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

Last Answer : Answer : D

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 : 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

Last Answer : Answer : B

This catalyzes formation of CoA derivatives from fatty acid, CoA and ATP: (A) Acyl CoA dehydrogenase (B) Enoyl hydrase (C) β-OH acyl CoA dehydrogenase (D) Thio kinase

Description : This catalyzes formation of CoA derivatives from fatty acid, CoA and ATP: (A) Acyl CoA dehydrogenase (B) Enoyl hydrase (C) β-OH acyl CoA dehydrogenase (D) Thio kinase

Last Answer : Answer : D

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 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

Last Answer : Answer : C

Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) Aldehydes are more sterically hindered than esters. (c) Once the nucleophile adds to an aldehyde, the tetrahedral intermediate is too sterically hindered to eliminate one of the attached groups. (d) Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

Description : Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) ... adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

Last Answer : Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

Which of the following characterizes the reactions of aldehydes and ketones? (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic acyl substitution (d) nucleophilic addition; free radical addition

Description : Which of the following characterizes the reactions of aldehydes and ketones? (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic acyl substitution (d) nucleophilic addition; free radical addition

Last Answer : nucleophilic addition; free radical addition

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 aminoacyl – tRNA to bacterial ribosomes (d) Selective inhibition of ribosomal peptidyl transferases (e) Inhibition of DNA–dependent RNA polymerase

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

A functional group designated—COOH is known as a/an a. Carboxyl. b. Carbonyl. c. Amino. d. Hydroxyl.

Description : A functional group designated—COOH is known as a/an a. Carboxyl. b. Carbonyl. c. Amino. d. Hydroxyl.

Last Answer : a. Carboxyl.

Site in the ribosome from which the tRNA donates amino acids to the growingpolypeptide chain is A- P site B- O site C- T site D- A site

Description : Site in the ribosome from which the tRNA donates amino acids to the growing polypeptide chain is A- P site B- O site C- T site D- A site

Last Answer : P site

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 : 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

Last Answer : Answer : D

A characteristic of protein synthesis in both the archaea and eukarya is A.transcription and translation are coupled B.translation is inhibited by diphtheria toxin C.proteins are synthesized from D-, rather than L-, isomers of amino acids D.the initiator tRNA is charged with N-formyl- methionine

Description : A characteristic of protein synthesis in both the archaea and eukarya is A.transcription and translation are coupled B.translation is inhibited by diphtheria toxin C.proteins are synthesized from D-, ... L-, isomers of amino acids D.the initiator tRNA is charged with N-formyl- methionine

Last Answer : C.proteins are synthesized from

A characteristic of protein synthesis in both the archaea and eukarya is A- transcription and translation are coupled B- translation is inhibited by diphtheria toxin C- .proteins are synthesized from D-, rather than L-, isomers of amino acids D- the initiator tRNA is charged with N-formyl-methionine

Description : A characteristic of protein synthesis in both the archaea and eukarya is A- transcription and translation are coupled B- translation is inhibited by diphtheria toxin C- .proteins are synthesized from D-, rather than L-, isomers of amino acids D- the initiator tRNA is charged with N-formyl-methionine

Last Answer : .proteins are synthesized from D-, rather than L-, isomers of amino acids

FAD containing enzyme, catalyzing formation of α, β unsaturated fatty acyl CoA derivative. (A) Acyl CoA dehydrogenase (B) Enoyl hydrase (C) β-OH acyl CoA dehydrogenase (D) Thiolase

Description : FAD containing enzyme, catalyzing formation of α, β unsaturated fatty acyl CoA derivative. (A) Acyl CoA dehydrogenase (B) Enoyl hydrase (C) β-OH acyl CoA dehydrogenase (D) Thiolase

Last Answer : Answer : A

Among the given compounds, the most susceptible to nucleophilic attack at the cabonyl group is:

Description : Among the given compounds, the most susceptible to nucleophilic attack at the cabonyl group is:

Last Answer : Among the given compounds, the most susceptible to nucleophilic attack at the cabonyl group is: A. `MeCOCl` B. `MeCHO` C. `MeCOOMe` D. `MeCOOCOMe`

Phenol is an ortho-para director because the hydroxyl group : (a) donates electrons that increase electron density at ortho and para positions favoring nucleophilic attack. (b) donates electrons that increase electron density at ortho and para positions favoring electrophilic attack. (c) donates electrons to the ortho and para positions and attracts electrons away from meta positions favoring nucleophilic attack of the ring. (d) donates electrons to the ortho and para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.

Description : Phenol is an ortho-para director because the hydroxyl group : (a) donates electrons that increase electron density at ortho and para positions favoring nucleophilic attack. (b) donates ... para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.

Last Answer : donates electrons that increase electron density at ortho and para positions favoring electrophilic attack.

Which one of the following transfers acyl groups? (A) Thiamine pyrophosphate (B) Lipomide (C) ATP (D) NADH

Description : Which one of the following transfers acyl groups? (A) Thiamine pyrophosphate (B) Lipomide (C) ATP (D) NADH

Last Answer : Answer : B