Tyrosine hydroxylase is inhibited by (A) Catecholamines (B) α−Methyldopa (C) Phenylalanine (D) Vanillyl mandelic acid

1 Answer

Answer :

Answer :  A

Related questions

Description : Albinism is due to deficiency of the enzyme: (A) Phenylalanine hydroxylase (B) Tyrosinase (C) p-Hydroxyphenylpyruvic acid oxidase (D) Tyrosine dehydrogenase

Last Answer : Answer : C

Description : All the following statements about phenylketonuria are correct except (A) Phenylalanine cannot be converted into tyrosine (B) Urinary excretion of phenylpyruvate and phenyllactate is increased (C) It ... diet (D) It leads to decreased synthesis of thyroid hormones, catecholamines and melanin

Last Answer : Answer : D

Description : The rate limiting step in the biosynthesis of catecholamines is (A) Decarboxylation of dihydroxyphenylalanine (B) Hydroxylation of phenylalanine (C) Hydroxylation of tyrosine (D) Oxidation of dopamine

Last Answer : Answer : C

Description : The rate limiting step in catecholamine synthesis is catalysed by (A) Phenylalanine hydroxylase (B) Tyrosine hydroxylase (C) Dopa decarboxylase (D) Phenylethanolamine N-methyl transferase

Last Answer : Answer : B

Description : For Catecholamine biosynthesis the rate limiting enzyme is (A) DOPA decarboxylase (B) DOPAMINE β-hydroxylase (C) Tyrosine hydroxylase (D) Phenylalanine hydroxylase

Last Answer : Answer : C

Description : Neonatal tyrosinemia is due to deficiency of the enzyme: (A) p-Hydroxyphenylpyruvate hydroxylase (B) Fumarylacetoacetate hydrolase (C) Phenylalanine hydroxylase (D) Tyrosine dehydrogenase

Last Answer : Answer : B

Description : Richner-Hanhart syndrome is due to defect in (A) Tyrosinase (B) Phenylalanine hydroxylase (C) Hepatic tyrosine transaminase (D) Fumarylacetoacetate hydrolase

Last Answer : Answer : B

Description : The rate limiting enzyme in the synthesis of catecholamines is: A. Tyrosine hydroxylase B. Dopa decarboxylase C. Dopamine β-hydroxylase D. Noradrenaline N-methyl transferase

Last Answer : A. Tyrosine hydroxylase

Description : The rate limiting enzyme in the synthesis of catecholamines is: A. Tyrosine hydroxylase B. Dopa decarboxylase C. Dopamine β-hydroxylase D. Noradrenaline N-methyl transferase

Last Answer : A. Tyrosine hydroxylase

Description : Dopa decarboxylase is inhibited by (A) Epinephrine (B) Norepinephrine (C) α−Methyldopa (D) None of these

Last Answer : Answer : C

Description : Maple syrup urine disease results from absence or serve deficiency of (A) Homogentisate oxidase (B) Phenylalanine hydroxylase (C) Branched chain amino acid transaminase (D) None of these

Last Answer : Answer : D

Description : All the following are true about phenylketonuria except (A) Deficiency of phenylalanine hydroxylase (B) Mental retardation (C) Increased urinary excretion of p-hydroxyphenyl pyruvic acid (D) Decrease serotonin formation

Last Answer : Answer : C

Description : The biosynthesis of both Catecholamine and serotonin require (A) Tyrosine hydroxylase (B) N-methyl transferase (C) Aromatic amino acid decarboxylase (D) Tryptophan pyrrolase

Last Answer : Answer : B

Description : Thyroid hormones are synthesized by the iodination of the amino acid: (A) Glycine (B) Phenylalanine (C) Alanine (D) Tyrosine

Last Answer : Answer : D

Description : A characteristic of pheochromocytoma is elevated urinary excretion of (A) Dopamine (B) Tyrosine (C) Vinylmandelic acid (D) Phenylalanine

Last Answer : Answer : C

Description : Activation or inactivation of certain key regulatory enzymes is accomplished by covalent modification of the amino acid: (A) Tyrosine (B) Phenylalanine (C) Lysine (D) Serine

Last Answer : Answer : D

Description : Which one of the following is an essential amino acid? (A) Arginine (B) Tyrosine (C) Phenylalanine (D) Proline

Last Answer : Answer : C

Description : The limiting amino acid of rice is (A) Lysine (B) Tryptophan (C) Phenylalanine (D) Tyrosine

Last Answer : Answer : A

Description : Million-Nasse’s reaction is specific for the amino acid: (A) Tryptophan (B) Tyrosine (C) Phenylalanine (D) Arginine

Last Answer : Answer : B

Description : Absence of phenylalanine hydroxylase causes (A) Neonatal tyrosinemia (B) Phenylketonuria (C) Primary hyperoxaluria (D) Albinism

Last Answer : Answer : D

Description : Hydroxylation of phenylalanine requires all of the following except (A) Phenylalanine hydroxylase (B) Tetrahydrobiopterin (C) NADH (D) Molecular oxygen

Last Answer : Answer : C

Description : In the synthetic pathway of epinephrine, disulfiram (antabuse) inhibits the enzyme: (A) Tyrosine hydroxylase (B) Dopamine β-hydroxylase (C) DOPA decarboxylase (D) N-methyl transferase

Last Answer : Answer : B

Description : Selenium is a constituent of the enzyme: (A) Glutathione peroxidase (B) Homogentisate oxidase (C) Tyrosine hydroxylase (D) Phenylalanin hydroxylase

Last Answer : Answer : A

Description : The deficiency of copper decreases the activity of the enzyme: (A) Lysine oxidase (B) Lysine hydroxylase (C) Tyrosine oxidase (D) Proline hydroxylase

Last Answer : Answer : A

Description : Tyrosinosis is due to defect in the enzyme: (A) Fumarylacetoacetate hydrolase (B) p-Hydroxyphenylpyruvate hydroxylase (C) Tyrosine transaminase (D) Tyrosine hydroxylase

Last Answer : Answer : A

Description : All the following statements about albinism are correct except (A) Tyrosine hydroxylase (tyrosinase) is absent or deficient in melanocytes (B) Skin is hypopigmented (C) It results in mental retardation (D) Eyes are hypopigmented

Last Answer : Answer : C

Description : Conversion of tyrosine to dihydroxyphenylalanine is catalysed by tyrosine hydroxylase which requires (A) NAD (B) FAD (C) ATP (D) Tetrahydrobiopterin

Last Answer : Answer : D

Description : Melatonin is synthesised from (A) Phenylalanine (B) Tyrosine (C) Tryptophan (D) None of these

Last Answer : Answer : C

Description : Niacin can be synthesised in human beings from (A) Histidine (B) Phenylalanine (C) Tyrosine (D) Tryptophan

Last Answer : Answer : D

Description : Million’s test is positive for (A) Phenylalanine (B) Glycine (C) Tyrosine (D) Proline

Last Answer : Answer : C

Description : Serotonin is synthesised from (A) Serine (B) Phenylalanine (C) Tyrosine (D) Tryptophan

Last Answer : Answer : D

Description : Phenylalanine is the precursor of (A) L-DOPA (B) Histamine (C) Tyrosine (D) Throxine

Last Answer : C

Description : Urinary excretion of vanillyl madelic acid is increased in (A) Phaeochromocytoma (B) Cushing’s syndrome (C) Carcinoid syndrome (D) Aldosteronism

Last Answer : Answer : A

Description : .Khorana first deciphered the triplet codons of (a) serine and isoleucine (b) cysteine and valine (c) tyrosine and tryptophan (d) phenylalanine and methinonine.

Last Answer : (a) serine and isoleucine

Description : Khorana first deciphered the triplet codons of (a) serine and isoleucine (b) cysteine and valine (c) tyrosine and tryptophan (d) phenylalanine and methinonine

Last Answer : (b) cysteine and valine

Description : Niacin can be synthesised in human beings from (A) Histidine (B) Phenylalanine (C) Tyrosine (D) Tryptophan

Last Answer : (D) Tryptophan

Description : Pure (R) Mandelic acid has specific rotation of 150. If a sample contains 60% of the R and 40% of its enantiomer, the `[alpha]` of his solution is.

Last Answer : Pure (R) Mandelic acid has specific rotation of 150. If a sample contains 60% of the R and 40% of its enantiomer, the `[alpha]` of his solution is.

Description : Benzaldehyde reacts with acetic anhydride in the presence of sodium acetate at 180°C to give : (a) Mandelic acid (b) Cinnamic acid (c) Malonic acid (d) Benzoic acid

Last Answer : Cinnamic acid

Description : Choose the correct statement about methenamine (hexamine): A. It acts by getting converted to mandelic acid in the urinary tract B. It releases formaldehyde in acidic urine which inturn kills ... acute urinary tract infections D. It is the preferred urinary antiseptic in patients with liver disease

Last Answer : B. It releases formaldehyde in acidic urine which inturn kills bacteria

Description : An enzyme involved in catabolism of catecholamines is (A) Dopa decarboxylase (B) Aromatic amino acid decarboxylase (C) Monoamine oxidase (D) Catechol oxidas

Last Answer : Answer : C

Description : The chief metabolite of catecholamines is (A) Metanephrine (B) Normetanephrine (C) 3, 4-Dihydroxymandelic acid (D) Vanillylmandelic acid

Last Answer : Answer : D

Description : In the B chain of insulin molecule, the Nterminal amino acid is (A) Proline (B) Threonine (C) Phenylalanine (D) Lysine

Last Answer : Answer : C

Description : In A chain of the insulin molecule the Nterminal amino acid is (A) Glycine (B) Valine (C) Serine (D) Phenylalanine

Last Answer : Answer : A

Description : The amino acid which synthesizes many hormornes: (A) Valine (B) Phenylalanine (C) Alanine (D) Histidine

Last Answer : Answer : B

Description : Phenylalanine, ornithine and methionine are involved in the biogenesis of (A) Lysergic acid (B) Reserpine (C) L-Hyoscyamine (D) Papaverine

Last Answer : Answer : A

Description : The amino acid containing an indole ring: (A) Tryptophan (B) Arginine (C) Threonine (D) Phenylalanine

Last Answer : Answer : A

Description : Seratonin is derived in the body from the following amino acid: (A) Phenylalanine (B) Histidine (C) Tryptophan (D) Serine

Last Answer : Answer : C

Description : Secretion of catecholamines is increased in (A) Cushing’s syndrome (B) Addison’s disease (C) Phaeochromocytoma (D) Simmond’s disease

Last Answer : Answer : C

Description : Phosphoinositide cascade is activated on binding of catecholamines to (A) α1-Adrenergic receptors (B) α2-Adrenergic receptors (C) β1-Adrenergic receptors (D) β2-Adrenergic receptors

Last Answer : Answer : A

Description : Binding of catecholamines to α2− adrenergic receptors (A) Increases the intracellular concentration of cAMP (B) Increases the intracellular concentration of cGMP (C) Decreases the intracellular concentration of cAMP (D) Decreases the intracellular concentration of cGMP

Last Answer : Answer : C