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 : 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
Last Answer : Answer : 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 : Tryptophan could be considered as precursor of (A) Melanotonin (B) Thyroid hormones (C) Melanin (D) Epinephrine
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 : Formation of melanin from tyrosine requires the action of (A) Dopa decarboxylation (B) Diamine oxidase (C) Peroxidase (D) Tyrosinase
Description : A common intermediate in the synthesis of all the steroid hormones is (A) Pregnenolone (B) 17-Hydroxypregnenolone (C) Corticosterone (D) Progesterone
Description : An enzyme required for the synthesis of thyroid hormones is (A) Iodinase (B) Deiodinase (C) Thyroperoxidase (D) Thyroxine synthetase
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 : Name the hormone which stimulates the synthesis and secretion of thyroid hormones from the thyroid gland.
Last Answer : Name the hormone which stimulates the synthesis and secretion of thyroid hormones from the thyroid gland.
Description : Hormones thyroxine, adrenaline and the pigment melanin are formed from (a) tyrosine (b) proline (c) tryptophan (d) glycine.
Last Answer : (a) tyrosine
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 : Insulin like growth hormones are produced by (A) Hypophysis (B) Liver (C) Pancreas (D) Thyroid
Description : Protein bound iodine is _________ bound to protein. (A) Iodine (B) Thyroid hormones (C) Thyroxine (D) Tri iodo thyronine
Description : Secretion of thyroid hormones is regulated by (A) Hypothalamus (B) Anterior pituitary (C) Feedback regulation (D) All of these 220 MCQs IN BIOCHEMISTRY
Description : Receptors for thyroid hormones are present (A) On the cell membrane (B) Across the cell membrane (C) Inside the cells (D) In association with G-proteins
Description : Thyroid hormones are present in blood (A) In free form (B) In association with thyroxine binding globulin (TBG) (C) In association with thyroxine binding prealbumin (TBPA) (D) Mainly in association with TBG, partly in free form and sometimes in association with TBPA also
Description : Thyroid hormones are synthesized by the iodination of the amino acid: (A) Glycine (B) Phenylalanine (C) Alanine (D) Tyrosine
Description : Excess secretion of thyroid hormones causes (A) Hyperthyroidism (B) Myxoedema (C) Cretinism (D) Cushing syndrome
Description : Xanthosine monophosphate is an intermediate during de novo synthesis of (A) TMP (B) CMP (C) AMP (D) GMP
Description : Inosine monophophate is an intermediate during the de novo synthesis of (A) AMP and GMP (B) CMP and UMP (C) CMP and TMP (D) All of these
Description : A common intermediate in the synthesis of estrogens is (A) Cortisol (B) Andostenedione (C) Corticosterone (D) 11-Deoxycorticosterone
Description : A common intermediate in the synthesis of cortisol and aldosterone is (A) Progesterone (B) Testosterone (C) Estradiol (D) None of these
Description : Each of the following can be an intermediate in the synthesis of phosphatidyl choline except (A) Phosphatidyl inositol (B) CDP-choline (C) Phosphatidyl ethanolamine (D) Diacylglycerol
Description : Intermediate in the denovo synthesis of triacyl glycerols include all the following except (A) Fatty acyl CoA (B) CDP diacyl glycerol (C) Glycerol-3-phosphate (D) Lysophosphatidic acid
Description : All the following correctly describe the intermediate 3-OH-3-methyl glutaryl CoA except (A) It is generated enzymatically in the mitochondrial matrix (B) It is formed in the cytoplasm (C) It inhibits the first step in cholesterol synthesis (D) It is involved in the synthesis of ketone bodies
Description : Which one of the following compounds is a key intermediate in the synthesis of both triacyl glycerols and phospholipids? (A) CDP Choline (B) Phosphatidase (C) Triacyl glyceride (D) Phosphatidyl serine
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
Description : All statements regarding 3-OH-3 methyl glutaryl CoA are true except (A) It is formed in the cytoplasm (B) Required in ketogenesis (C) Involved in synthesis of Fatty acid (D) An intermediate in cholesterol biosynthesis
Description : Glycogenin is (A) Uncoupler of oxidative phosphorylation (B) Polymer of glycogen molecules (C) Protein primer for glycogen synthesis (D) Intermediate in glycogen breakdown
Last Answer : C
Description : Tyrosine hydroxylase is inhibited by (A) Catecholamines (B) α−Methyldopa (C) Phenylalanine (D) Vanillyl mandelic acid
Description : Secretion of catecholamines is increased in (A) Cushing’s syndrome (B) Addison’s disease (C) Phaeochromocytoma (D) Simmond’s disease
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
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
Description : The chief metabolite of catecholamines is (A) Metanephrine (B) Normetanephrine (C) 3, 4-Dihydroxymandelic acid (D) Vanillylmandelic acid
Description : Posterior pituitary gland secretes (A) Catecholamines (B) Oxytocin (C) Follicle stimulating hormone (D) Serotonin
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 : An amino acid used for the synthesis of thyroid hormone is (A) Tyrosine (B) Tryptophan (C) Histidine (D) Proline
Description : Dopa decarboxylase is inhibited by (A) Epinephrine (B) Norepinephrine (C) α−Methyldopa (D) None of these
Description : Immediate precursor of epinephrine is (A) Metanephrine (B) Norepinephrine (C) Dopa (D) Dopamine
Description : Blood brain barrier can be crossed by (A) Epinephrine (B) Dopamine (C) Dopa (D) All of these
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 : For Catecholamine biosynthesis the rate limiting enzyme is (A) DOPA decarboxylase (B) DOPAMINE β-hydroxylase (C) Tyrosine hydroxylase (D) Phenylalanine hydroxylase
Description : Phenylalanine is the precursor of (A) L-DOPA (B) Histamine (C) Tyrosine (D) Throxine
Description : Hormones (A) Act as coenzyme (B) Act as enzyme (C) Influence synthesis of enzymes (D) Belong to B-complex group
Description : Acetyl CoA formed from pyruvate can be used for the synthesis of all the following except (A) Glucose (B) Fatty acids (C) Cholesterol (D) Steroid hormones
Description : MSH causes (A) Dispersal of melanin granules in melanocytes (B) Increase in melanin concentration in melanocytes (C) Decerease in melanin concentration in melanocytes (D) Increase in number of melanocytes
Description : Retina contains this photosensitive pigment: (A) Rhodopsin (B) Opsin (C) Retinol (D) Melanin
Description : The highest concentration of cystine can be found in (A) Melanin (B) Chondroitin sulphate (C) Myosin (D) Keratin