Description : The cardiac muscarinic receptors: A. Are of the M1 subtype B. Are of the M2 subtype C. Are selectively blocked by pirenzepine D. Function through the PIP2 → IP3/DAG pathway
Last Answer : B. Are of the M2 subtype
Description : All of the following subserve as intracellular second messengers in receptor mediated signal transduction except: A. Cyclic AMP B. Inositol trisphosphate C. Diacyl glycerols D. G proteins
Last Answer : D. G proteins
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 : Histamine H2 blockers attenuate the gastric secretory response to acetylcholine and pentagastrin as well because: A. H2 blockers block gastric mucosal cholinergic and gastrin receptors as well B. H2 ... acetylcholine and gastrin all act through the phospholipase C-IP3:DAG pathway in gastric mucosa
Last Answer : C. Acetylcholine and gastrin act partly by releasing histamine in gastric mucosa
Description : a2–adrenergic receptors are associated with following except (a) Increase in phospholipase C activity (b) Increase in potassium channel conductance (c) Decrease in calcium channel conductance (d) Increase in adenylyl cyclase activity
Last Answer : Ans: D
Description : The following receptor has an intrinsic ion channel: A. Histamine H1 receptor B. Histamine H2 receptor C. Adrenergic alfa receptor D. GABA-benzodiazepine receptor
Last Answer : D. GABA-benzodiazepine receptor
Description : Beta adrenergic blockers lower intraocular tension by: A. Down regulating adenylyl cyclase in ciliary body through reduced activation of β2 adrenoceptors B. Constricting ciliary blood vessels ... action on trabecular meshwork D. Reducing aqueous formation unrelated to beta adrenoceptor mediation
Last Answer : A. Down regulating adenylyl cyclase in ciliary body through reduced activation of β2 adrenoceptors
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 : 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 : 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 : Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an all or none' action on a ... lock and key' structural features D. Properties of affinity' and intrinsic activity' are independently variable
Last Answer : D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable
Description : The cardiac muscarinic receptors (a) Are of the M1 subtype (b) Are of the M2 subtype (c) Are selectively blocked by pirenzepine (d) Function through the PIP2 ? IP3/DAG pathway
Last Answer : Ans: B
Description : Muscarinic cholinergic receptors: A. Are located only on parasympathetically innervated effector cells B. Mediate responses by opening an intrinsic Na+ ion channel C. Are present on vascular endothelium which has no cholinergic nerve supply D. Predominate in the autonomic ganglia
Last Answer : C. Are present on vascular endothelium which has no cholinergic nerve supply
Description : Drugs that block the a receptor on effector cells at adrenergic nerve endings (a) Antagonize the effects of isoproterenol on the heart rate (b) Antagonize some of the effects of epinephrine on ... the effects of epinephrine on adenylyl cyclase (d) Cause mydriasis (e) Decreases blood glucose levels
Description : Which does NOT occur in a cell stimulated by a steroid hormone? A) The steroid hormone enters the cell by crossing the plasma membrane. B) The hormone binds to a receptor molecule in the ... activates certain genes. E) DNA is transcribed, mRNA is translated, and the result is protein synthesis.
Last Answer : C) The second messenger cyclic AMP is stimulated by the hormone-receptor complex. D) The hormone-receptor complex binds the chromatin and activates certain genes.
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 : Binding of insulin to its receptor activates (A) Adenylate cyclase (B) Guanylate cyclase (C) Phospholipase C (D) Tyrosine kinase
Last Answer : Answer : D
Description : Receptor agonists possess: A. Affinity but no intrinsic activity B. Intrinsic activity but no affinity C. Affinity and intrinsic activity with a + sign D. Affinity and intrinsic activity with a – sign
Last Answer : C. Affinity and intrinsic activity with a + sign
Description : Which of the following is not the basis for subclassifying β adrenergic receptors into β1 and β2 : A. Selectivity of agonists B. Selectivity of antagonists C. Transducer pathway of response effectuation D. Organ selective location
Last Answer : C. Transducer pathway of response effectuation
Description : Which of the following is not the basis for subclassifying β adrenergic receptors into β 1 and β 2: A. Selectivity of agonists B. Selectivity of antagonists C. Transducer pathway of response effectuation D. Organ selective location
Description : The GABAB receptor: A. Is an intrinsic ion channel containing receptor B. Mediates neuronal depolarization C. Is insensitive to blockade by bicuculline D. Regulates intracellular cAMP
Last Answer : C. Is insensitive to blockade by bicuculline
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 is associated with a steroid hormone? A) cyclic AMP B) the second messenger system C) production of new proteins D) activation of proteins present in an inactive form E) binding of a protein to a surface receptor on the plasma membrane
Last Answer : C) production of new proteins
Description : The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor
Last Answer : C. Suppression of maximal agonist response
Description : Which of the following is a G protein coupled receptor: A. Muscarinic cholinergic receptor B. Nicotinic cholinergic receptor C. Glucocorticoid receptor D. Insulin receptor
Last Answer : A. Muscarinic cholinergic receptor
Description : Agonists affect the receptor molecule in the following manner: A. Alter its amino acid sequence B. Denature the receptor protein C. Alter its folding or alignment of subunits D. Induce covalent bond formation
Last Answer : C. Alter its folding or alignment of subunits
Last Answer : C. Both ligand recognition and signal transduction
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 : Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of ... C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein
Last Answer : D. Increased synthesis of enzyme protein
Description : The plasma protein bound fraction of a drug: A. Contributes to the response at the given moment B. Remains constant irrespective of the total drug concentration C. Remains constant irrespective of the disease state D. Is not available for metabolism unless actively extracted by the liver
Last Answer : D. Is not available for metabolism unless actively extracted by the liver
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 : The following are true about parathyroid hormone a. it is an 84 amino acid peptide hormone b. it increases calcium absorption from the gastrointestinal tract c. it acts on a cell surface receptor that increases intracellular cyclic AMP d. all above
Last Answer : all above
Description : A partial agonist can antagonise the effects of a full agonist because it has: A. High affinity but low intrinsic activity B. Low affinity but high intrinsic activity C. No affinity and low intrinsic activity D. High affinity but no intrinsic activity
Last Answer : A. High affinity but low intrinsic activity
Description : Which of the following statements about the coagulation cascade is/are true? A. The intrinsic pathway of coagulation is the predominant pathway in vivo for hemostasis and coagulation. ... coagulation abnormalities. D. Deficiencies of factor XII cause severe clinical bleeding syndromes.
Last Answer : Answer: AC DISCUSSION: Although it was previously held that two somewhat distinct pathways existed for the activation of the coagulation cascade, it is now recognized that the predominant ... bleeding. This further emphasizes the secondary role that the intrinsic pathway plays in coagulation
Description : A receptor which itself has enzymatic property is: A. Insulin receptor B. Progesterone receptor C. Thyroxine receptor D. Glucagon receptor
Last Answer : A. Insulin receptor
Description : What is true in relation to drug receptors: A. All drugs act through specific receptors B. All drug receptors are located on the surface of the target cells C. Agonists induce a conformational change in the receptor D. Partial agonists have low affinity for the receptor
Last Answer : C. Agonists induce a conformational change in the receptoR
Description : Agonistic action on which of the following adrenergic receptors located on ciliary epithelial cells reduces aqueous secretion: A. β1 receptor B. β2 receptor C. α1 receptor D. α2 receptor
Last Answer : D. α2 receptor
Description : 81. Which one of the following pairs of hormones are the examples of those that can easily pass through the cell membrane of the target cell and bind to a receptor inside it (mostly in the nucleus) (1) Cortisol, testosterone (2) Insulin, glucagon (3) Thyroxin, Insulin (4) Somatostatin, oxytocin
Last Answer : Cortisol, testosterone