Description : The following enzymes on the left are responsible for the synthesis of the neurotransmitters on the right: a. monoamine oxidase: noradrenaline b. cholinesterase: acetylcholine c. catechol-o-methyl transferase: dopamine d. dopa decarboxylase: adrenaline
Last Answer : dopa decarboxylase: adrenaline
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 : Epinephrine is rapidly metabolized by (A) Monoamine oxidase (B) Deaminase (C) Transminase (D) Decarboxylase
Last Answer : Answer : A
Description : The enzyme involved in variegate porphyria is (A) Protoporphyrinogen oxidase (B) Coproporphyrinogen oxidase (C) Uroporphyrinogen decarboxylase (D) ALA 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
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 : 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 : 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 : The biosynthesis of both Catecholamine and serotonin require (A) Tyrosine hydroxylase (B) N-methyl transferase (C) Aromatic amino acid decarboxylase (D) Tryptophan pyrrolase
Description : At the adrenergic synapse, the concentration of adrenaline in synaptic cleft: a. increased by cocaine which inhibit reuptake of adrenaline b. decreased by MAO (monoamine oxidase) - inhibitors c. controlled chiefly by the activity of the enzyme COMT d. increased by noradrenaline receptor blockers
Last Answer : increased by cocaine which inhibit reuptake of adrenaline
Description : All the following statements about serotonin are true except (A) It causes vasolidatation (B) It causes bronchoconstriction (C) It is metabolized by monoamine oxidase (D) Its metabolite is 5-hydroxyindole acetic acid
Description : Conversion of uroporphyrinogen III to coprophyrinogen III is catalysed by the enzyme.: (A) Uroporphyrinogen decarboxylase (B) Coproporphyrinogen oxidase (C) Protoporphyrinogen oxidase (D) Ferrochelatase
Description : The defective enzyme in histidinemia is (A) Histidine carboxylase (B) Histidine decarboxylase (C) Histidase (D) Histidine oxidase
Description : Methyl dopa decreases blood pressure by (A) Inhibiting the synthesis of catecholamines (B) Antagonising the action of aldosterone (C) Stimulating the release of renin (D) Inhibiting the breakdown of angiotensin
Description : DOPA is an intermediate in the synthesis of (A) Thyroid hormones (B) Catecholamines (C) Melanin (D) Catecholamines and melanin
Last Answer : Answer : D
Description : Physostigmine is a competitive inhibitor of (A) Xanthine oxidase (B) Cholinesterase (C) Carbonic anhydrase (D) Monoamine oxidase
Description : Dopa decarboxylase is inhibited by (A) Epinephrine (B) Norepinephrine (C) α−Methyldopa (D) None of these
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 : Formation of melanin from tyrosine requires the action of (A) Dopa decarboxylation (B) Diamine oxidase (C) Peroxidase (D) Tyrosinase
Description : Schardinger’s enzyme is (A) Lactate dehydrogenase (B) Xanthine dehydrogenase (C) Uric oxidase (D) L amino acid dehydrogenase
Description : Which of the following categories of medications may result in seizure activity if withdrawn suddenly? a) Tranquilizers Abrupt withdrawal of tranquilizers may result in anxiety, tension, ... may cause excessive respiratory depression during anesthesia due to an associated electrolyte imbalance.
Last Answer : a) Tranquilizers Abrupt withdrawal of tranquilizers may result in anxiety, tension, and even seizures if withdrawn suddenly.
Description : Methyldopa lowers BP by: A. Inhibiting dopa decarboxylase in adrenergic nerve endings B. Generating α-methyl noradrenaline in brain which reduces sympathetic tone C. Generating α-methyl ... as a false transmitter in peripheral adrenergic nerve endings D. Activating vascular dopamine receptors
Last Answer : B. Generating α-methyl noradrenaline in brain which reduces sympathetic tone
Description : The enzyme trypsin is specific for peptide bonds of (A) Basic amino acids (B) Acidic amino acids (C) Aromatic amino acids (D) Next to small amino acid residues
Description : Enzymic deficiency in β-aminoisobutyric aciduria is (A) Adenosine deaminase (B) Xanthine oxidase (C) Orotidylate decarboxylase (D) Transaminase
Description : Acute intermittent porphyria (paraoxymal porphyria) is caused due to deficiency of (A) Uroporphyrinogen I synthase (B) ALA synthase (C) Coproporphyrinogen oxidase (D) Uroporphyrinogen decarboxylase
Description : The enzyme involved in congenial erythropoietic porphyria is (A) Uroporphyrinogen I synthase (B) Uroporphyrinogen III cosynthase (C) Protoporphyrinogen oxidase (D) Ferrochelatase
Description : Which of the following is not an enzyme involved in glycolysis? (A) Euolase (B) Aldolose (C) Hexokinase (D) Glucose oxidase
Last Answer : D
Description : An enzyme of pyrimidine nucleotide biosynthesis sensitive to allosteric regulation is (A) Aspartate transcarbamoylase (B) Dihydroorotase (C) Dihydroorotate dehydrogenase (D) Orotidylic acid decarboxylase
Description : Conversion of deoxyuridine monophosphate to thymidine monophosphate is catalysed by the enzyme: (A) Ribonucleotide reductase (B) Thymidylate synthetase (C) CTP synthetase (D) Orotidylic acid decarboxylase
Description : The α-ketoacid is decarboxylated by H2O2 forming a carboxylic acid with one carbon atom less in the absence of the enzyme: (A) Catalase (B) Decarboxylase (C) Deaminase (D) Phosphatase
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
Description : A molybdenum containing oxidase is (A) Cytochrome oxidase (B) Xanthine oxidase (C) Glucose oxidase (D) L-Amino acid oxidase
Description : The activity of mammalian L-amino acid oxidase, an FMN – flavo protein, is quite (A) Slow (B) Rapid (C) Both (A) and (B) (D) None of these
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 : Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may ... involved the catalytic production of superoxide anion (O 2 ) by the enzyme xanthine oxidase.
Last Answer : Answer: ABCD DISCUSSION: Oxidants are reactive oxygen metabolites that have both physiologic and pathophysiologic roles. As potent oxidizing agents, oxidants are involved in cytochrome P ... leukocyte infiltration and activation, causing further tissue damage by the release of cytotoxic proteases
Description : A drug which prevents uric acid synthesis by inhibiting the enzyme Xanthine oxidase is (A) Aspirin (B) Allopurinal (C) Colchicine (D) Phenyl benzoate
Description : In humans purine are catabolised to uric acid due to lack of the enzyme: (A) Urease (B) Uricase (C) Xanthine oxidase (D) Guanase
Description : Albinism is due to deficiency of the enzyme: (A) Phenylalanine hydroxylase (B) Tyrosinase (C) p-Hydroxyphenylpyruvic acid oxidase (D) Tyrosine dehydrogenase
Description : Fabry’s disease is due to the deficiency of the enzyme: (A) Ceramide trihexosidase (B) Galactocerebrosidase (C) Phytanic acid oxidase (D) Sphingomyelinase
Description : A drug which prevents uric acid synthesis by inhibiting the enzyme xanthine oxidase is (A) Aspirin (B) Allopurinol (C) Colchicine (D) Probenecid
Last Answer : B
Description : Degradation of proteins to amino acids, glucose from carbohydrates and fatty acids from lipids is known as (A) Anabolism (B) Metabolism (C) Catabolism (D) Cretinism
Description : Sulphur containing amino acids after catabolism produces a substance which is excreted: (A) SO2 (B) HNO3 (C) H2SO4 (D) H3PO4
Description : Edman’s reaction can be used to (A) Determine the number of tyrosine residues in a protein (B) Determine the number of aromatic amino acid residues in a protein (C) Determine the amino acid sequence of a protein (D) Hydrolyse the peptide bonds in a protein
Description : An aromatic amino acid is (A) Lysine (B) Tyrosine (C) Taurine (D) Arginine
Last Answer : (B) Tyrosine
Description : Orotic aciduria type II reflects the deficiency of the enzyme: (A) Orotate phosphoribosyl transferase (B) Orotidylate decarboxylase (C) Dihydroorotase (D) Dihydroorotate dehydrogenase
Description : Histamine is formed from histidine by the enzyme histidine decarboxylase in the presence of (A) NAD (B) FMN (C) HS-CoA (D) B6-PO4
Description : The enzyme catalyzing conversion of androstenedione to testosterone is a (A) Oxygenase (B) Dehydrogenase (C) Isomerase (D) Decarboxylase
Description : Biotin is a coenzyme of the enzyme (A) Carboxylase (B) Hydroxylase (C) Decarboxylase (D) Deaminase