Description : The enzyme catalyzing conversion of androstenedione to testosterone is a (A) Oxygenase (B) Dehydrogenase (C) Isomerase (D) Decarboxylase
Last Answer : Answer : B
Description : 3-β-Hydroxysteroid dehydrogenase and ∆5,4 isomerase catalyse the conversion of the weak androgen DHEA to (A) Androstenedione (B) Testosterone (C) Progesterone (D) Estrone
Last Answer : Answer : A
Description : In the biosynthesis of cortiol, the sequence of enzymes involved is (A) Hydroxylase–dehydrogenase + isomerase – hydroxylase (B) Dehydrogenase–hydroxylase–isomerase (C) Hydroxylase–lyase–dehydrogenase isomerase (D) Isomerase–lyase–hydroxylase–dehydrogenase
Description : Pyruvate dehydrogenase is a/an (A) Isomerase (B) Lyase (C) Ligase (D) Oxido reductase
Last Answer : Answer : D
Description : Formation of acetyl CoA from pyruvate for de novo synthesis of fatty acids requires (A) Pyruvate dehydrogenase complex (B) Citrate synthetase (C) ATP citrate lyase (D) All of these
Description : Urease is a (A) Lyase (B) Ligase (C) Isomerase (D) Hydrolase
Description : Which of the following is an allosteric enzyme? (A) Phosphohexose isomerase (B) Phosphotriose isomerase (C) Lactate dehydrogenase (D) Phosphofructokinase
Description : Hemolytic anemia is caused by the deficiency of certain enzymes of the pentose phosphate pathway, the principal enzyme involved is (A) Glucose-6-phosphate dehydrogenase (B) Aldolase (C) Fructose 1, 6-bisphosphatase (D) Phosphohexose isomerase
Description : In glycolytic pathway, iodacetate inhibits the activity of the enzyme: (A) Phosphotriose isomerase (B) Glyceraldehyde-3-phosphate dehydrogenase (C) Pyruvate kinase (D) Phosphofructokinase
Description : A common intermediate in the synthesis of cortisol and aldosterone is (A) Progesterone (B) Testosterone (C) Estradiol (D) None of these
Description : The defect in adrenal cortex responsible for lack of glucocorticoids and mineralcorticoids is (A) Androstenedione deficiency (B) 17 α -OH progesterone deficiency (C) C-21 hydroxylase deficiency (D) Testosterone deficiency HORMONE METABOLISM 209
Last Answer : Answer : C
Description : Acetyl-CoA is the principal building block of fatty acids. It is produced within the mitochondria and does not diffuse readily into cytosol. The availability of acetyl CoA involves (A) Carnitine acyl transferase (B) Pyruvate dehydrogenase (C) Citrate lyase (D) Thiolase
Description : Acetyl CoA required for extra mitochondrial fatty acid synthesis is produced by (A) Pyruvate dehydrogenase complex (B) Citrate lyase (C) Thiolase (D) Carnitine-acyl transferase
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 : One of the enzymes regulating glycolysis is (A) Phosphofructokinase (B) Glyceraldehyde-3-phosphate dehydrogenase (C) Phosphotriose isomerase (D) Phosphohexose isomerase
Description : Cyclic AMP is formed from ATP by the enzyme adenylate cyclase which is activated by the hormone: (A) Insulin (B) Epinephrine (C) Testosterone (D) Progesterone
Last Answer : B
Description : Blood pressure may be increased by the excessive secretion of (1) Thyroxine (2) Testosterone (3) Estradiol (4) Estrol
Last Answer : (1) Thyroxine Explanation: With its excess secretion, also known as hyper secretion, thyroxin (T4) causes an increased heart rate, high blood pressure, possible palpitations, and could lead to heart failure. It is related to hyperthyroidism.
Last Answer : Thyroxine
Description : A cofactor in the conversion of dihydroorotate to orotic acid, catalysed by the enzyme dihydroorotate dehydrogenase is (A) FAD (B) FMN (C) NAD (D) NADP
Description : Conversion of fructose to sorbitol is catalysed by the enzyme: (A) Sorbitol dehydrogenase (B) Aldose reductase (C) Fructokinase (D) Hexokinase
Description : The formation of ∆2-trans-enoyl-CoA from acyl-CoA requires the enzyme: (A) Acyl-CoA synthetase (B) Acyl-CoA dehydrogenase (C) 3-Hydroxy acyl-CoA dehydrogenase (D) Thiolase
Description : The enzyme -ketoglutarate dehydrogenase in the citric acid cycle requires (A) Lipoate (B) Folate (C) Pyridoxine (D) Inositol
Description : Dihydroxyacetone phosphate and glyceraldehyde-3-phosphate are intercoverted by CARBOHYDRATES AND CARBOHYDRATE METABOLISM 13 (A) Triose isomerase (B) Phosphotriose isomerase (C) Diphosphotriose isomerase (D) Dihydroxyacetone phosphorylase
Description : An enzyme required for the synthesis of ketone bodies as well as cholesterol is (A) Acetyl CoA carboxylase (B) HMG CoA synthetase (C) HMG CoA reductase (D) HMG CoA lyase
Description : Conversion of testosterone to dihydrotestosterone by the enzyme 5α-reductase is required for the following actions except: A. Formation of male external genitalia in the foetus B. Prostatic hypertrophy in elderly males C. Pubertal changes in the male adolescent D. Spermatogenesis
Last Answer : D. Spermatogenesis
Description : In biosynthesis of cholesterol triparanol inhibits the activity of the enzyme: (A) ∆24 Reductase (B) Oxidosqualene-lanosterol cyclase (C) Isomerase (D) Squalene epoxidase ENZYMES 155
Description : Essential fructosuria is characterized by the lack of the hepatic enzyme: (A) Phosphohexose isomerase (B) Aldalose A (C) Aldolase B (D) Fructokinase
Description : Hereditary fructose intolerance involves the absence of the enzyme: (A) Aldalose B (B) Fructokinase (C) Triokinase (D) Phosphotriose isomerase
Description : The enzyme involved in essential pentosuria is (A) Reductase (B) Hydroxylase (C) Isomerase (D) Racemase
Description : An enzyme involved in gluconeogenesis is (A) Pyruvate kinase (B) Pyruvate carboxylase (C) Hexokinase (D) Phosphohexose isomerase
Description : Alkaptonuria occurs due to deficiency of the enzyme: (A) Maleylacetoacetate isomerase (B) Homogentisate oxidase (C) p-Hydroxyphenylpyruvate hydroxylase (D) Fumarylacetoacetate hydrolase
Description : The enzyme phosphoenolpyruvate carboxykinase catalyses the conversion of oxaloacetate to phosphoenolpyruvate requires (A) ATP (B) ADP (C) AMP (D) GTP
Description : The enzyme dopamine β-oxidase which catalyses conversion of dopamine to norepinephrine requires (A) Vitamin A (B) Vitamin C (C) Vitamin E (D) Vitamin B12
Description : Covalent modification of an enzyme generally requires a (A) Hormone (B) cAMP (C) Protein kinase (D) All of these
Description : Most of the energy in aerobic respiration of glucose is captured by 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 : electron transport of electrons from NADH
Description : Which of the following is an amino acid derived hormone? (a) Epinephrine (b) Ecdysone (c) Estradiol (d) Estriol
Last Answer : (a) Epinephrine
Description : The estrogen commonly used for hormone replacement therapy in menopausal women is: A. Ethinylestradiol B. Estradiol benzoate C. Diethylstilbestrol D. Conjugated estrogens
Last Answer : D. Conjugated estrogen
Description : Which of the following is an amino acid derived hormone ? (1) Epinephrine (2) Ecdysone (3) Estradiol (4) Estriol
Last Answer : (1) Epinephrine
Description : In the biosynthesis of testosterone the rate limiting step is conversion of (A) Cholesterol to pregnenolone (B) Pregnenolone to progesterone (C) Progesterone to 17 α-hydroxy progesterone (D) 17 α-Hydroxy progesterone to androstenedione
Description : Progesterone is transported in blood by (A) Transcortin (B) Sex hormone binding globulin (C) Albumin (D) Testosterone estrogen binding globulin
Description : Secretion of luteinising hormone is increased by (A) GnRH (B) FSH (C) Testosterone (D) None of these
Description : In males, secretion of luteinising hormone is inhibited by (A) Gonadotropin releasing hormone (B) FSH (C) High blood level of testosterone (D) Inhibin
Description : All the following statements about FSH are true except (A) It is a tropic hormone secreted by anterior pituitary (B) Its secretion is increased by gonadotropin releasing hormone (C) It acts on Sertoli cells (D) It increases the synthesis of testosterone
Description : Conversion of inosine monophosphate to xanthine monophosphate is catalysed by (A) IMP dehydrogenase (B) Formyl transferase (C) Xanthine-guanine phosphoribosyl transferase (D) Adenine phosphoribosyl transferase
Description : Conversion of pyruvate into acetyl CoA is catalysed by (A) Pyruvate dehydrogenase (B) Didrolipoyl acetyl transferase (C) Dihydrolipoyl dehydrogenase (D) All the 3 acting in concert
Description : The initial step of the citric acid cycle is (A) Conversion of pyruvate to acetyl-CoA (B) Condensation of acetyl-CoA with oxaloacetate (C) Conversion of citrate to isocitrate (D) Formation of α -ketoglutarate catalysed by isocitrate dehydrogenase
Description : Conversion of glucose to glucose-6- phosphate in human liver is by (A) Hexokinase only (B) Glucokinase only (C) Hexokinase and glucokinase (D) Glucose-6-phosphate dehydrogenase
Last Answer : C
Description : Which one of the following enzymes requires a coenzyme derived from the vitamin whose structure is shown below? (A) Enoyl CoA hydratase (B) Phosphofructokinase (C) Glucose-6-phosphatase (D) Glucose-6-phosphate dehydrogenase
Description : UDP glucose is converted to UDP glucurronate, a reaction catalysed by UDP glucose dehydrogenase requires (A) NAD+ (B) FAD (C) NADP (D) FMN
Description : The reaction catalysed by α-ketoglutarate dehydrogenase in the citric acid cycle requires (A) NAD (B) NADP (C) ADP (D) ATP