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
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 : 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 : Albinism is a congenital disorder resulting from the lack of which enzyme? (a) Tyrosinase (b) Xanthine oxidase (c) Catalase (d) Fructokinase
Last Answer : (a) Tyrosinase
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 : The enzyme using some other substance, not oxygen as hydrogen acceptor is (A) Tyrosinase (B) Succinate dehydrogenase (C) Uricase (D) Cytochrome oxidase
Description : Alkaptonuria occurs due to deficiency of the enzyme: (A) Maleylacetoacetate isomerase (B) Homogentisate oxidase (C) p-Hydroxyphenylpyruvate hydroxylase (D) Fumarylacetoacetate hydrolase
Description : For Catecholamine biosynthesis the rate limiting enzyme is (A) DOPA decarboxylase (B) DOPAMINE β-hydroxylase (C) Tyrosine hydroxylase (D) Phenylalanine hydroxylase
Description : Absence of phenylalanine hydroxylase causes (A) Neonatal tyrosinemia (B) Phenylketonuria (C) Primary hyperoxaluria (D) Albinism
Description : Selenium is a constituent of the enzyme: (A) Glutathione peroxidase (B) Homogentisate oxidase (C) Tyrosine hydroxylase (D) Phenylalanin hydroxylase
Description : Tyrosine hydroxylase is inhibited by (A) Catecholamines (B) α−Methyldopa (C) Phenylalanine (D) Vanillyl mandelic acid
Description : Formation of melanin from tyrosine requires the action of (A) Dopa decarboxylation (B) Diamine oxidase (C) Peroxidase (D) Tyrosinase
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
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 : The rate limiting step in catecholamine synthesis is catalysed by (A) Phenylalanine hydroxylase (B) Tyrosine hydroxylase (C) Dopa decarboxylase (D) Phenylethanolamine N-methyl transferase
Description : Tyrosinosis is due to defect in the enzyme: (A) Fumarylacetoacetate hydrolase (B) p-Hydroxyphenylpyruvate hydroxylase (C) Tyrosine transaminase (D) Tyrosine hydroxylase
Description : Ehlers-Danlos syndrome characterized by hypermobile joints and skin abnormalities is due to (A) Abnormality in gene for procollagen (B) Deficiency of lysyl oxidase (C) Deficiency of prolyl hydroxylase (D) Deficiency of lysyl hydroxylase
Description : Vitamin K is involved in posttranslational modification of the blood clotting factors by acting as cofactor for the enzyme: (A) Carboxylase (B) Decarboxylase (C) Hydroxylase (D) Oxidase
Description : Schardinger’s enzyme is (A) Lactate dehydrogenase (B) Xanthine dehydrogenase (C) Uric oxidase (D) L amino acid dehydrogenase
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
Description : Fabry’s disease is due to the deficiency of the enzyme: (A) Ceramide trihexosidase (B) Galactocerebrosidase (C) Phytanic acid oxidase (D) Sphingomyelinase
Description : Which one of the following statements concerning glucose-6-phosphate dehydrogenase deficiency is correct? (A) Young R.B.Cs, particularly reticulocytes, contain the highest enzyme activity cells show less enzyme ... PD gene (D) G-6-PD deficiency is precipitated by ingestion of drugs such as aspirin
Description : An inborn error, maple syrup urine disease is due to deficiency of the enzyme: (A) Isovaleryl-CoAhydrogenase (B) Phenylalnine hydroxylase (C) Adenosyl transferase (D) α-Ketoacid decarboxylase
Description : Vitamin K is involved in posttranslational modification of the blood clotting factors by acting as cofactor for the enzyme (A) Carboxylase (B) Decarboxylase (C) Hydroxylase (D) Oxidase
Last Answer : (A) Carboxylase
Description : An enzyme catalyzing oxidoreduction, using oxygen as hydrogen acceptor is (A) Cytochrome oxidase (B) Lactate dehydrogenase (C) Malate dehydrogenase (D) Succinate dehydrogenase
Description : Example of an extracellular enzyme is (A) Lactate dehydrogenase (B) Cytochrome oxidase (C) Pancreatic lipase (D) Hexokinase
Description : Refsum’s disease is due to deficiency of the enzyme: (A) Pytantate-α-oxidase (B) Glucocerebrosidase (C) Galactocerebrosidase (D) Ceramide trihexosidase
Description : An example of competitive inhibition of an enzyme is the inhibition of a. Succinic dehydrogenase by malonic acid b. Cytochrome oxidase by cyanide c. Hexokinase by glucose-6-phosphate d. Carbonic anhydrase by carbon dioxide
Last Answer : Ans: A
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 biosynthesis of both Catecholamine and serotonin require (A) Tyrosine hydroxylase (B) N-methyl transferase (C) Aromatic amino acid decarboxylase (D) Tryptophan pyrrolase
Description : Thyroid hormones are synthesized by the iodination of the amino acid: (A) Glycine (B) Phenylalanine (C) Alanine (D) Tyrosine
Description : A characteristic of pheochromocytoma is elevated urinary excretion of (A) Dopamine (B) Tyrosine (C) Vinylmandelic acid (D) Phenylalanine
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
Description : Which one of the following is an essential amino acid? (A) Arginine (B) Tyrosine (C) Phenylalanine (D) Proline
Description : The limiting amino acid of rice is (A) Lysine (B) Tryptophan (C) Phenylalanine (D) Tyrosine
Description : Million-Nasse’s reaction is specific for the amino acid: (A) Tryptophan (B) Tyrosine (C) Phenylalanine (D) Arginine
Description : The “Primaquin sensitivity types of haemolytic anaemia has been found to relate to reduced R.B.C activity of which enzyme? (A) Pyruvate kinase deficiency (B) Glucose-6-phosphatase deficiency (C) Glucose-6-p dehydrogenase deficiency (D) Hexokinase deficiency
Last Answer : C
Description : Hydroxylation of phenylalanine requires all of the following except (A) Phenylalanine hydroxylase (B) Tetrahydrobiopterin (C) NADH (D) Molecular oxygen
Description : Which of the following enzyme defects is associated with a characteristic body odour? 1) Phenylalanine aminotransferase 2) Galactose0-phosphate-uridyltransferase 3) Ornithine transcarbamylase deficiency 4) Fumaryl acetoacetase 5) Branched chain ketoacid decarboxylase
Last Answer : Answers-5 The following inborn errors of amino acid metabolism are associated with abnormal odours: Glutaric acidaemia type II (sweaty feet), hawkinsinuria (swimming pool), isovaleric acidaemia (sweaty feet), ... The general rule is that if a child smells peculiar he requires a metabolic work-up.
Description : Acute hemolytic episode after administration of antimalarial, primaquin, is due to deficiency of the enzyme: (A) 6-Phosphogluconate dehydrogenase (B) Glucose-6-phosphate dehydrogenase (C) Epimerase (D) Transketolase
Description : Acute hemolytic anemia in person’s sensitive to the Fava beans is due to the deficiency of the enzyme: (A) Pyruvate dehydrogenase (B) G-6-PD (C) Aconitase (D) Transketolase
Description : Most of the ammonia released from L-αamino acids reflects the coupled action of transaminase and (A) L-glutamate dehydrogenase (B) L-amino acid oxidase (C) Histidase (D) Serine dehydratase
Description : Conversion of tyrosine to dihydroxyphenylalanine is catalysed by tyrosine hydroxylase which requires (A) NAD (B) FAD (C) ATP (D) Tetrahydrobiopterin
Description : Melatonin is synthesised from (A) Phenylalanine (B) Tyrosine (C) Tryptophan (D) None of these
Description : Niacin can be synthesised in human beings from (A) Histidine (B) Phenylalanine (C) Tyrosine (D) Tryptophan
Description : Million’s test is positive for (A) Phenylalanine (B) Glycine (C) Tyrosine (D) Proline
Description : Serotonin is synthesised from (A) Serine (B) Phenylalanine (C) Tyrosine (D) Tryptophan
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