Description : The best understood intracellular messenger is cyclic AMP (cAMP). Which of the following statement(s) concerning this intracellular messenger is/are correct? a. Intracellular cyclic AMP is constantly ... of adenylate cyclase d. cAMP is the only cyclic nucleotide active as an intracellular messenger
Last Answer : Answer: a, b The prototypic intracellular messenger is cAMP. To function as a mediator, the concentration of cAMP must change rapidly. In resting cells, cAMP is continuously being degraded by ... produce cGMP. Intracellular calcium ions also serve as second messengers in a large number of cells
Description : Binding of insulin to its receptor activates (A) Adenylate cyclase (B) Guanylate cyclase (C) Phospholipase C (D) Tyrosine kinase
Last Answer : Answer : D
Description : Which of the following statement(s) is/are true concerning cell membrane receptors? a. The largest family of cell surface receptors are the G-protein-linked receptors b. Activities of the ... through the use adenylate cyclase d. Tyrosine kinase receptors are considered G-protein-linked receptors
Last Answer : Answer: a, c All water-soluble regulatory molecules bind to the cell surface receptor proteins. Binding of the appropriate ligand evokes an intracellular signal which usually regulates ... are adenylate cyclase, which converts ATP to cAMP, and the polyphosphoinositide-specific phospholipase C
Description : Whcih of the following hormone does not activate adenylate cyclase? (A) Epinephrine (B) Glucagon (C) Parathyroid hormone (D) Insulin
Description : Binding of thyroxine to its receptors (A) Activates Adenylate cyclase (B) Activates guanylate cyclase (C) Activates a stimulatory G-protein (D) Increases transcription
Description : Adenylate cyclase is activated by (A) GDP-bearing α-Subunit of G-protein (B) GTP-bearing α-Subunit of G-protein (C) GDP-bearing γ-Subunit of G-protein (D) GTP-bearing γ-Subunit of G-protein
Last Answer : Answer : B
Description : Adenylate cyclase is activated by (A) Insulin (B) Glucagon (C) Prostaglandin E1 (D) Ca2+ ions
Description : Rod cells possess a trans-membrane protein which is (A) Adenylate cyclase (B) Transducin (C) Rhodopsin (D) B as well as C
Last Answer : Answer : C
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 : Which of the following is activated by Cholera toxin? 1) Adenylate cyclase 2) Guanlyate cyclase 3) Peroxisome proliferator receptor (PPAR) gamma 4) Sodium/potassium ATPase 5) The glucose-sodium transporter
Last Answer : Answers-1 Cholera toxin activates adenylate cyclase with generation of cAMP.
Description : Insulin decreases the activity of (A) cAMP dependent protein kinase (B) HMG CoA-reductas (C) Phosphodiesterase (D) Acetyl CoA-carboxylase
Last Answer : Answer : A
Description : The enzyme that converts glucose to glucose-6-phosphate is (A) Phosphatase (B) Hexokinase (C) Phosphorylase (D) Glucose synthetase
Description : In conversion of lactic acid to glucose, three reactions of glycolytic pathway are circumvented, which of the following enzymes do not participate? (A) Pyruvate carboxylase (B) Phosphoenol pyruvate carboxy kinase (C) Pyruvate kinase (D) Glucose-6-phosphatase
Description : Glucose-6-phosphatase and PEP carboxy kinase are regulated by (A) Covalent modification (B) Allosteric regulation (C) Induction and repression (D) All of these
Description : The first enzyme found to have isoenzymes was (A) Alkaline Phosphatase (B) Lactate dehydrogenase (C) Acid Phosphatase (D) Creatine kinase
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 : In conversion of Lactic acid to Glucose, three reactions of Glycolytic pathway are circumvented, which of the following enzymes do not participate? (A) Pyruvate Carboxylase (B) Phosphoenol pyruvate carboxy kinase (C) Pyruvate kinase (D) Glucose-6-phosphatase
Description : The 4 rate limiting enzymes of gluconeogenesis are (A) Glucokinase, Pyruvate carboxylae phosphoenol pyruvate carboxykinase and glucose-6-phosphatase (B) Pyruvate carboxylase, phosphoenol ... fructokinase, pyruvate carboxylase, phosphoenol pyruvate carboxykinase and fructose 1, 6 diphosphatase
Description : The following is an enzyme required for glycolysis: (A) Pyruvate kinase (B) Pyruvate carboxylase (C) Glucose-6-phosphatase (D) Glycerokinase
Last Answer : A
Description : An enzyme of pyrimidine nucleotides biosynthesis regulated at the genetic level by apparently coordinate repression and derepression is (A) Carbamoyl phosphate synthetase (B) Dihydroorotate dehydrogenase (C) Thymidine kinase (D) Deoxycytidine kinase
Description : Phosphorylation of adenosine to AMP is catalysed by (A) Adenosine kinase (B) Deoxycytidine kinase (C) Adenylosuccinase (D) Adenylosuccinate synthetase
Description : Cholesterol by a feed back mechanism inhibits the activity of (A) HMG-CoA synthetase (B) HMG-CoA reductase (C) Thilase (D) Mevalonate kinase
Description : In the biosynthesis of cholesterol, the rate limiting enzyme is (A) Mevalonate kinase (B) HMG-CoA synthetase (C) HMG-CoA reductase (D) Cis-prenyl transferase
Description : HMG-CoA is converted to mevalonate by reduction catalysed by (A) HMG-CoA synthetase (B) HMG-CoA reductase (C) Mevalonate kinase (D) Thiolase
Description : Insulin has no effect on the activity of the enzyme: (A) Glycogen synthetase (B) Fructokinase (C) Pyruvate kinase (D) Pyruvate dehydrogenase
Description : The rage limiting step cholesterol biosynthesis is (A) Squalene synthetase (B) Mevalonate kinase (C) HMG CoA synthetase (D) HMG CoA reductase
Description : In sugarcane plant 14CO2 is fixed to malic acid, in which the enzyme that fixes CO2 is (a) ribulose biphosphate carboxylase (b) phosphoenol pyruvic acid carboxylase (c) ribulose phosphate kinase (d) fructose phosphatase.
Last Answer : (b) phosphoenol pyruvic acid carboxylase
Description : The adipose tissue lacks the enzyme _____________. a. Glycerol Kinase. b. Lipase. c. Glycerol Synthetase. d. Pyrophosphatase.
Last Answer : a. Glycerol Kinase.
Description : Ultraviolet light can damage a DNA strand causing (A) Two adjacent purine residue to form a covalently bounded dimer (B) Two adjacent pyrimidine residues to form covalently bonded dimer (C) Disruption of phosphodiesterase linkage (D) Disruption of non-covalent linkage
Description : Insulin increases the permeability of glucose across the plasma membrane of muscle cells by (A) Acting on adenylate cycle (B) By loosening the integrity of the membrane (C) Through Ca2 ... membrane cruting the hexose carries of intracellular organelles and making them fuse with the plasma membrane
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 : Cromolyn has as its major action (a) Block of calcium channels in lymphocytes (b) Block of mediator release from mast cells (c) Block of phosphodiesterase in mast cells and basophils (d) Smooth muscle relaxation in the bronchi (e) Stimulation of cortisol release by the adrenals
Last Answer : Ans: B
Description : Methylxanthines exert the following action (s) at cellular/molecular level (a) Intracellular release of Ca2+ (b) Antagonism of adenosine (c) Inhibition of phosphodiesterase (d) All of the above
Last Answer : Ans: D
Description : Milrinone is an example of (a) Phosphodiesterase I inhibitor (b) Phosphodiesterase II inhibitor (c) Phosphodiesterase III inhibitor (d) Phosphodiesterase IV inhibitor
Last Answer : Ans: C
Description : Methylxanthine drugs such as aminophylline cause which one of the following? (a) Vasoconstriction in many vascular beds (b) Decrease in the amount of cAMP in mast cells (c) Bronchodilation (d) Activation of the enzyme phosphodiesterase (e) Sedation
Description : Corticosteroids exert anti-inflammatory action by inhibiting the following enzyme (a) Cycloxygenase (b) Lipozygenase (c) Phospholipase - A (d) Phosphodiesterase
Description : Corticosteroids exert antiinflammatory action by inhibiting the following enzyme: A. Cyclooxygenase B. Lipoxygenase C. Phospholipase-A D. Phosphodiesterase
Last Answer : C. Phospholipase-A
Description : Methylxanthines exert the following action(s) at cellular/molecular level: A. Intracellular release of Ca2+ B. Antagonism of adenosine C. Inhibition of phosphodiesterase D. All of the above
Last Answer : D. All of the above
Description : Glucocorticoids increase the synthesis of all of the following except (A) Glucokinase (B) Glucose-6-phosphatase (C) Fructose-1, 6-biphosphatase (D) Pyruvate carboxylase
Description : Hyperglycemic effect of glucocorticoids is due to (A) Inactivation of protein phosphatase (B) Inactivation of fructose 1,6-biphosphatase (C) Stimulation of synthesis of pyruvate carboxylase (D) Stimulation of synthesis of eltroxykinase
Description : Zinc is a cofactor for (A) Acid phosphatase (B) Alkaline phosphatase (C) Amylase (D) Lipase
Description : Calcitriol facilitates calcium absorption by increasing the synthesis of the following in intestinal mucosa: (A) Calcium Binding Protein (B) Alkaline Phosphatase (C) Calcium-dependent ATPase (D) All of these
Description : Serum alkaline phosphatase is greatly increased in (A) Haemolytic jaundice (B) Hepatic jaundice (C) Obstructive jaundice (D) None of these
Description : Cobalt may act as cofactor for the enzyme: (A) Glycl-glycine dipeptidase (B) Elastase (C) Polynucleotidases (D) Phosphatase
Description : An inherited or acquired renal tubular defect in the reabsorption of phosphate (Vit D resistant ricket) is characterized with (A) Normal serum Phosphate (B) High serum phosphate (C ... blood phosphorous with elevated alkaline Phosphate (D) A high blood phosphorous with decreased alkaline phosphatase
Description : Which of the following enzyme typically elevated in alcoholism? (A) Serum ALP (B) Serum GOT (C) Serum γ-GT (D) Serum acid phosphatase
Description : Which of the following is known as bone forming enzyme? (A) Alkaline phosphatase (B) Acid phosphatase (C) Leucine aminopeptidase (D) γ-glutamyl transpeptidase
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 : All of the following are zinc-containing enzymes except (A) Acid Phosphatase (B) Alkaline Phosphatase (C) Carbonic anhydrase (D) RNA polymerase
Description : Alkaline phosphatase is present in (A) Liver (B) Bones (C) Intestinal mucosa (D) All of these