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 : Conversion of uridine diphosphate into deoxyuridine diphosphate requires all the following except (A) Ribonucleotide reductase (B) Thioredoxin (C) Tetrahydrobiopterin (D) NADPH
Last Answer : Answer : C
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 : All of the following are required for hydroxylation of proline residues except (A) Ascorbic acid (B) Glutamate (C) Ferrous ions (D) Molecular oxygen
Last Answer : Answer : B
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
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 : Tyrosine hydroxylase is inhibited by (A) Catecholamines (B) α−Methyldopa (C) Phenylalanine (D) Vanillyl mandelic acid
Last Answer : Answer : A
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 : For Catecholamine biosynthesis the rate limiting enzyme is (A) DOPA decarboxylase (B) DOPAMINE β-hydroxylase (C) Tyrosine hydroxylase (D) Phenylalanine hydroxylase
Description : Neonatal tyrosinemia is due to deficiency of the enzyme: (A) p-Hydroxyphenylpyruvate hydroxylase (B) Fumarylacetoacetate hydrolase (C) Phenylalanine hydroxylase (D) Tyrosine dehydrogenase
Description : Albinism is due to deficiency of the enzyme: (A) Phenylalanine hydroxylase (B) Tyrosinase (C) p-Hydroxyphenylpyruvic acid oxidase (D) Tyrosine dehydrogenase
Description : Richner-Hanhart syndrome is due to defect in (A) Tyrosinase (B) Phenylalanine hydroxylase (C) Hepatic tyrosine transaminase (D) Fumarylacetoacetate hydrolase
Description : Absence of phenylalanine hydroxylase causes (A) Neonatal tyrosinemia (B) Phenylketonuria (C) Primary hyperoxaluria (D) Albinism
Description : All of the following statements about thioredoxin reductase are true except: (A) It requires NADH as a coenzyme (B) Its substrates are ADP, GDP, CDP and UDP (C) It is activated by ATP (D) It is inhibited by dADP
Description : De novo synthesis of fatty acids requires all of the following except (A) Biotin (B) NADH (C) Panthothenic acid (D) ATP
Description : Conversion of a procarcinogen into a carcinogen often requires (A) Proteolysis (B) Microsomal hydroxylation (C) Exposure to ultraviolet radiation (D) Exposure to X-rays
Description : All the following statement about hydroxyproline are true except (A) There is no codon for hydroxyproline (B) It is present in large amounts in collagen (C) Free proline cannot be hydroxylated to hydroxyproline (D) Hydroxylation of proline residues is catalysed by a dioxygenase
Description : DNA ligase of E. coli requires which of the following co-factors? (A) FAD (B) NAD+ (C) NADP+ (D) NADH
Description : Thyroproxidase requires hydrogen peroxide as oxidizing agent. The H2O2 is produced by (A) FADH2 dependent enzyme (B) NADH dependent enzyme (C) NADP dependent enzyme (D) NADPH dependent enzyme
Description : In the biosynthesis of heme, condensation between succinyl CoA and glycine requires (A) NAD+ (B) FAD (C) NADH + H+ (D) B6-phosphate
Description : Conversion of all-trans-retinal into alltrans-retinol requires (A) NAD (B) NADH (C) NADP (D) NADPH
Description : Conversion of retinal into ritonal requires the presence of (A) NADH (B) NADPH (C) FADH2 (D) Lipoic acid
Description : Conversion of folate into tetrahydrofolate requires (A) NADH (B) NADPH (C) FMNH2 (D) FADH2
Description : Conversion of β-carotene into retinal requires the presence of (A) β-Carotene dioxygenase (B) Bile salts (C) Molecular oxygen (D) All of these
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
Description : All the following amino acids are optically active except (A) Tryptophane (B) Phenylalanine (C) Valine (D) Glycine
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
Description : Oxidative degradation of acetyl CoA in the citric acid cycle gives a net yield of all the following except (A) FADH2 (B) 3 NADH (C) 2 ATP (D) 2CO2
Description : During each cycle of on going fatty acid oxidation, all the following compounds are generated except (A) H2O (B) Acetyl CoA (C) Fatty acyl CoA (D) NADH FATS AND FATTY ACID METABOLISM 103
Description : During each cycle of β-oxidation of fatty acid, all the following compounds are generated except (A) NADH (B) H2O (C) FAD (D) Acyl CoA
Description : For glyburide, all of the following metabolic reactions are logical EXCEPT (A) O-demethylation (B) aromatic oxidation (C) benzylic hydroxylation (D) amide hydrolysis
Last Answer : (B) aromatic oxidation
Description : The acquisition energy by glucose fermentation requires A.substrate-level phosphorylation B.electron transport of electrons from NADH C.long-chain fatty acid oxidation D.the enzyme formic-hydrogen lyase
Last Answer : A.substrate-level phosphorylation
Description : Asseration: The thermal stability of hydrides of oxygen family decrease with molecular weight. Reason: The decomposition of `M-H` bond requires lesser
Last Answer : Asseration: The thermal stability of hydrides of oxygen family decrease with molecular weight. Reason: The decomposition ... in `O-H` than `S-H`.
Description : Which of the following is/are not a substrate or cofactor for prolyl hydroxylase? A. Alpha-ketoglutarate. B. Ascorbate. C. Biotin. D. Oxygen. E. Copper.
Last Answer : Answer: CE DISCUSSION: Prolyl hydroxylase is one of the rate-limiting enzymes in collagen synthesis. Substrates and cofactors such as iron, alpha-ketoglutarate, ascorbate, and oxygen are ... broken down. Thus, ascorbate deficiency (scurvy) and hypoxia have similar effects on collagen synthesis
Description : Epinephrine is derived from norepinephrine by (A) Decarboxylation (B) Hydroxylation (C) Oxidation (D) N-methylation
Description : The sequential steps in the conversion of tyrosine to epinephrine are (A) Ring hydroxylation-decarboxylation-side chain hydroxylation-N-methylation (B) Side chain hydroxylation-decarboxylation- ... chain hydroxylation-N-methylation (D) N-methylation-decarboxylation-ring and side chain hydroxylation
Description : Biotin is essential for (A) Translation (B) Carboxylation (C) Hydroxylation (D) Transamination
Description : In renal rickets, the following hydroxylation of Vitamin D3 does not take place: (A) 25 (B) 1 (C) 24 (D) 7
Description : Hydroxylation of 25-hydroxy cholecalciferol is promoted by (A) Cytochrome A (B) Panthyroid hormone (C) Cytochrome b (D) cAMP
Description : 25-hydroxylation of Vitamin D3 takes place in (A) Liver (B) Kidneys (C) Intestines (D) Pancreas
Description : 1-hydroxylation of 25-hydroxy Vitamin D3 takes place in (A) Liver (B) Kidneys (C) Intestine (D) Pancreas
Description : Biotin is involved in which of the following types of reactions? (A) Hydroxylation (B) Carboxylation (C) Decarboxylation (D) Deamination
Description : In retinal rickets, the following hydroxylation of Vitamin D3 does not take place: (A) 25 (B) 1 (C) 24 (D) 7
Description : Hydroxylation of 25-hydroxy cholecalciferol is promoted by (A) Cytochrome - a (B) Parathyroid hormone (C) Cytochrome-b (D) CAMP
Description : 25-hydroxylation of vitamin D3 takes place in (A) Liver (B) Kidneys (C) Intestine (D) Pancreas
Description : 1-hydroxylation of 25-OH vitamin D3 takes place in (A) Liver (B) Kidneys (C) Intestine (D) Pancreas
Description : 25-Hydroxylation of vitamin D occurs in (A) Skin (B) Liver (C) Kidneys (D) Intestinal mucosa
Description : Vitamin B1 coenzyme (TPP) is involved in (A) Oxidative decarboxylation (B) Hydroxylation (C) Transamination (D) Carboxylation
Description : Hydroxylation of Proline and Lysine in a protein is effected by (A) Vitamin B1 (B) Vitamin B2 (C) Vitamin B6 (D) Vitamin C
Description : Histidine is converted into histamine by (A) Carboxylation (B) Decarboxylation (C) Methylation (D) Hydroxylation