Description : Which one of the following statements concerning glucose metabolism is correct? (A) The conversion of Glucose to lactate occurs only in the R.B.C (B) Glucose enters most cells by a mechanism in ... ) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte
Last Answer : C
Description : Activated phospholipase C acts on (A) Phosphatidyl inositol-4, 5-biphosphate (B) Inositol-1, 4, 5-triphosphate (C) Protein kinase C (D) Pl-3 kinase
Last Answer : Answer : A
Description : Protein kinase C is activated by (A) Cyclic AMP (B) Cyclic GMP (C) Diacyl glycerol (D) Inositol triphosphate
Last Answer : Answer : C
Description : The protein IRS-1 is phosphorylated by (A) Protein kinase A (B) Protein kinase C (C) Tyrosine kinase activity of insulin receptor (D) Tyrosine kinase activity of IGF-1 receptor
Last Answer : Answer : B
Description : Insulin decreases the activity of (A) cAMP dependent protein kinase (B) HMG CoA-reductas (C) Phosphodiesterase (D) Acetyl CoA-carboxylase
Description : With regard to membrane receptors for hormones: a. they are often glycoproteins b. they are important for hormones made up of steroid c. those for insulin exhibit an intrinsic protein kinase activity d. glucagon uses calcium as a second messenger
Last Answer : they are often glycoproteins
Description : The insulin receptor is a: A. Ion channel regulating receptor B. Tyrosine protein kinase receptor C. G-protein coupled receptor D. None of the above
Last Answer : B. Tyrosine protein kinase receptor
Description : Mini-dose heparin has been shown to be useful in the prophylaxis of postoperative venous thrombosis. Mechanism(s) by which low-dose heparin is/are thought to protect against venous ... aggregation and subsequent platelet release action d. A mild prolongation of activated partial thromboplastin time
Last Answer : Answer: a, b, c Low-dose heparin is thought to protect against venous thrombosis through three different mechanisms. First, antithrombin III activity with its inhibition of activated Factor X is ... release reaction. The standard doses of heparin administered (5000 units bid) does not affect aPTT
Description : The antiviral action of amantadine is exerted through: A. Interaction with the viral M2 protein B. Interaction with a virus directed thymidine kinase C. Inhibition of a viral protease enzyme D. Inhibition of viral RNA mediated DNA synthesi
Last Answer : A. Interaction with the viral M2 protein
Description : What is the mechanism of action of insulin?
Last Answer : Insulin acts by binding to membrane receptor, on the target cells.
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 : Cholesterol by a feed back mechanism inhibits the activity of (A) HMG-CoA synthetase (B) HMG-CoA reductase (C) Thilase (D) Mevalonate kinase
Description : Activation of IRS-1, PI-3 kinase and GRB2 is brought about by (A) Glucagon (B) Insulin (C) Prolactin (D) IGF-2
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 : In the insulin receptor, tyrosine kinase domain is present in (A) α-Subunits (B) β-Subunits (C) γ-Subunits (D) δ-Subunits
Description : Tyrosine kinase activity is present in (A) α-Adrenergic receptors (B) β-Adrenergic receptors (C) Cholinergic receptors (D) Insulin receptors
Description : Insulin increases the activity of (A) Pyruvate kinase (B) Phosphorylase (C) Triacylglycerol kinase (D) Fructose 2, 6-bisphosphatase
Description : Insulin has no effect on the activity of the enzyme: (A) Glycogen synthetase (B) Fructokinase (C) Pyruvate kinase (D) Pyruvate dehydrogenase
Description : The mechanism of synthesis of DNA and RNA are similar to all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is (D) They require a primer
Description : The mechanism of synthesis of DNA and RNA are similar in all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is 5’ → 3’ (D) They require a primer
Description : __________ explains the mechanism of catalysis. (A) Activated complex theory (B) Collision theory (C) Thermodynamics (D) None of these
Last Answer : (A) Activated complex theory
Description : Adenylate cyclase is activated by (A) Insulin (B) Glucagon (C) Prostaglandin E1 (D) Ca2+ ions
Description : Acetyl CoA carboxylase is activated by (A) Citrate (B) Insulin (C) Both (A) and (B) (D) None of these
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 : What is the role of second messenger in the mechanism of protein hormone action? -Biology
Last Answer : answer:
Description : Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following ... are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis
Last Answer : Answer: a, b, d Penicillins, cephalosporins, and monobactams possess a b-lactam ring of some type and act to bind bacterial division plate proteins, thus inhibiting cell wall ... act in different mechanisms to inhibit protein synthesis, therefore two agents in combination act synergistically
Description : The most important mechanism by which tetracycline antibiotics exert antiimicrobial action is (a) They chelate Ca2+ ions and alter permeability of bacterial cell membrane (b) They bind to 30S ribosomes ... peptide chain in the bacteria (d) They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : Ans: B
Description : Identify A, B and C in the diagramatic representation of the mechanism of hormone action. B A Response 1 C Physiological Responses Select the correct option from the following. (a) A-Steroid Hormone; B- ... ; C - Second Messenger (d) A-Protein Hormone; B-Cyclic AMP; C-Hormone-receptor Complex
Last Answer : (b) A-Protein Hormone; B-Receptor; C-Cyclic AMP
Description : Trichloroacetic acid, a strong acid, has been used by dentists for chemical cautery of hypertrophic tissue and aphthous ulcers; its mechanism of action is, BOUCHERS P 194 A. Thermodynamic ... Activation of tissue enzymes C. Osmotic pressure D. Protein precipitation (PPT) E. Neutralization
Last Answer : D. Protein precipitation (PPT)
Description : The most important mechanism by which tetracycline antibiotics exert antimicrobial action is: A. They chelate Ca2+ ions and alter permeability of bacterial cell membrane B. They bind to 30S ribosomes ... peptide chain in the bacteria D. They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : B. They bind to 30S ribosomes and inhibit bacterial protein synthesis
Description : Vasoconstrictor effect of ADH is mediated by (A) cAMP (B) cGMP (C) Protein kinase C (D) Angiotensin II
Description : All the following statements about epidermal growth factor are true except (A) It is a protein (B) It possess quaternary structure (C) Its receptor is made up of a single polypeptide chain (D) Its receptor possesses tyrosine kinase domain
Description : Cyclic AMP binds to (A) Catalytic subunits of protein kinase (B) Regulatory subunits of protein kinase (C) Catalytic subunits of phosphorylase kinase (D) Regulatory subunits of phosphorylase kinase
Description : Covalent modification of an enzyme generally requires a (A) Hormone (B) cAMP (C) Protein kinase (D) All of these
Description : Adipose tissue lacks (A) Hormone-sensitive lipase (B) Glycerol kinase (C) cAMP-dependent protein kinase (D) Glycerol-3-phosphate dehydrogenase
Description : One of the following enzymes does not change glycogen synthase a to b. (A) Glycogen synthase kinases 3, 4, 5 (B) Ca2+ calmodulin phosphorylase kinase (C) Ca2+ calmodulin dependent protein kinase (D) Glycogen phosphorylase a
Last Answer : D
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 : 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 : What is a protein kinase?
Last Answer : The Cell Cycle Clock: Cyclins and Cyclin-Dependent Kinases •Two types of regulatory proteins are involved in cell cycle control: cyclins and cyclin-dependent kinases (Cdks)
Description : Agonist induced autophosphorylation, internalization and down regulation is a distinctive feature of: A. G-protein coupled receptors B. Intrinsic ion channel containing receptors C. Tyrosine protein kinase receptors D. Receptors regulating gene expression
Last Answer : C. Tyrosine protein kinase receptors
Description : Receptors perform the following function/functions: A. Ligand recognition B. Signal transduction C. Both ligand recognition and signal transduction D. Disposal of agonists and antagonists
Last Answer : D. Disposal of agonists and antagonists
Description : The following receptor type has 7 helical membrane spanning amino acid segments with 3 extracellular and 3 intracellular loops: A. Tyrosine protein kinase receptor B. Gene expression regulating receptor C. Intrinsic ion channel containing receptor D. G protein coupled receptor
Last Answer : D. G protein coupled receptor
Description : Which of the following is not a sulfonylurea but acts by analogous mechanism to bring about quick and brief insulin release that is useful for normalizing meal time glycaemic excursions in type 2 diabetes mellitus: A. Glimepiride B. Miglitol C. Repaglinide D. Rosiglitazone
Last Answer : C. Repaglinide
Description : Positive control of induction is best described as a control system in which an operon functions (A) Unless it is switched off by a derepressed repressor protein (B) Only after a repressor protein is ... on (D) Only after an inducer protein, which is activated by an inducer, switch it on
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
Description : As thrombin generation proceeds, the body has natural anticoagulant systems opposing further thrombus formation. Natural anticoagulants include: a. Tissue plasminogen activator (TPA) b. Antithrombin III c. Activated protein C d. Heparin cofactor II
Last Answer : Answer: b, c, d Just as thrombin generation is the key to coagulation, antithrombin III is the most central anticoagulant proteins. This glycoprotein binds to thrombin, preventing its removal of ... in the body. Therefore, TPA is part of the fibrinolytic system rather than a natural anticoagulant
Description : What is true about Bt toxin? (a) Bt protein exists as active toxin in the Bacillus. (b) The activated toxin enters the ovaries of the pest to sterilise it and thus prevent its multiplication. ... Bacillus has antitoxins. (d) The inactive protoxin gets converted into active form in the insect gut.
Last Answer : (d) The inactive protoxin gets converted into active form in the insect gut.
Description : Bacillus thuringiensis forms protein crystals which contain insecticidal protein. This protein (a) binds with epithelial cells of midgut of the insect pest ultimately killing it (b) is coded by several ... pest (d) does not kill the carrier bacterium which is itself resistant to this toxin.
Last Answer : (a) binds with epithelial cells of midgut of the insect pest ultimately killing it
Description : Which of the following statements is true? (A) Enzymes have names ending ase (B) Enzymes are highly specific in their action (C) Enzymes are living organisms (D) Enzymes get activated on heating