Description : Binding of thyroxine to its receptors (A) Activates Adenylate cyclase (B) Activates guanylate cyclase (C) Activates a stimulatory G-protein (D) Increases transcription
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 : cAMD is destroyed by (A) Adenylate cyclase (B) Phosphodiesterase (C) Synthetase phosphatase (D) Synthetase kinase
Last Answer : 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 : 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
Description : In the insulin receptor, tyrosine kinase domain is present in (A) α-Subunits (B) β-Subunits (C) γ-Subunits (D) δ-Subunits
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 : Whcih of the following hormone does not activate adenylate cyclase? (A) Epinephrine (B) Glucagon (C) Parathyroid hormone (D) Insulin
Description : Adenylate cyclase is activated by (A) Insulin (B) Glucagon (C) Prostaglandin E1 (D) Ca2+ ions
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 : 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 receptor transduction mechanism with the fastest time-course of response effectuation is: A. Adenylyl cyclase-cyclic AMP pathway B. Phospholipase C-IP3: DAG pathway C. Intrinsic ion channel operation D. Protein synthesis modulation
Last Answer : C. Intrinsic ion channel operation
Description : Phosphorylated IRS-1 activates GRB-2 which is (A) G-protein receptor binding protein-2 (B) Growth factor receptor binding protein-2 (C) Growth hormone receptor binding protein-2 (D) Glucocorticoid receptor binding protein-2 226 MCQs IN BIOCHEMISTRY
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 : Tyrosine kinase activity is present in (A) Acetylcholine receptor (B) PDGF receptor (C) ADH receptor (D) All of these
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 : 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 : Tyrosine kinase activity is present in (A) α-Adrenergic receptors (B) β-Adrenergic receptors (C) Cholinergic receptors (D) Insulin 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 : 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 : Insulin binding sites are present on the (A) α-subunits of insulin receptor (B) β-subunits of insulin receptor (C) γ-subunits of insulin receptor (D) α-and β−subunits of insulin receptor
Last Answer : Answer : A
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
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 : 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
Last Answer : Ans: B
Description : The dopamine D2 receptor has the following feature: A. It is excitatory in nature B. It is negatively coupled to adenyl cyclase C. It is selectively blocked by bromocriptine D. It is not blocked by metoclopramide
Last Answer : B. It is negatively coupled to adenyl cyclase
Description : Actions of 5-HT2 receptor activation are primarily mediated by: A. Increased membrane permeability to Na+ ions B. Increased formation of cAMP C. Activation of guanylyl cyclase D. Generation of inositol trisphosphate and diacyl glycerols
Last Answer : D. Generation of inositol trisphosphate and diacyl glycerols
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 : The mechanism of action of cyclosporine involves (a) Activation of calcineurin (b) Binding to cyclophilin to cause inhibition of a cytoplasmic phosphatase (c) Blockade of interleukin – 2- receptors (d) Inhibition of phospholipase A2 (e) Suppression of bone marrow progenitors
Description : Thyroperoxidase iodinates (A) Free tyrosine in thyroid gland (B) Tyrosine residues of thyroglobulin (C) Tyrosine residues of thyroxine binding globulin (D) Tyrosine residues of thyroxine binding prealbumin
Description : Calcium is important in skeletal muscle contraction because it (a) binds to troponin to remove the masking of active sites on actin for myosin (b) activates the myosin ATPase by binding to it ... filament (d) prevents the formation of bonds between the myosin cross bridges and the actin filament.
Last Answer : (a) binds to troponin to remove the masking of active sites on actin for myosin
Description : Calcium is important in skeletal muscle contraction because it :- (1) binds to troponin to remove the masking of active sites on actin for myosin. (2) activates the myosin ATPase by binding to ... filament. (4) prevents the formation of bonds between the myosin cross bridges and the actin filament.
Last Answer : (1) binds to troponin to remove the masking of active sites on actin for myosin.
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 : Activation of IRS-1, PI-3 kinase and GRB2 is brought about by (A) Glucagon (B) Insulin (C) Prolactin (D) IGF-2
Description : Insulin decreases the activity of (A) cAMP dependent protein kinase (B) HMG CoA-reductas (C) Phosphodiesterase (D) Acetyl CoA-carboxylase
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 : 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 : Binding of growth hormone to its receptor results in increased transcription of (A) c-fos gene (B) c-myc gene (C) p-53 gene (D) None of these
Description : Binding of growth hormone to its receptor results in phosphorylation of (A) JAK-2 (B) Growth hormone receptor (C) STATs (D) All of these
Description : Which one of the following hormones is derived most completely from tyrosine? (A) Glucagon (B) Thyroxine (C) Insulin (D) Prostaglandins
Description : In the B chain of insulin molecule, the C-terminal amino acid: (A) Threonine (B) Tyrosine (C) Glutamate (D) Valine
Description : In the A chain of insulin molecule the Cterminal amino acid is (A) Asparagine (B) Threonine (C) Valine (D) Tyrosine
Description : Fibronectin has binding sites for all of the following except (A) Glycophorin (B) Collagen (C) Heparin (D) Integrin receptor
Description : The only correct statement about hormone receptors is (A) Receptors for protein hormones are present in cytosol (B) Receptors for steroid hormones are membrane bound (C) Hormone-receptor binding is irreversible (D) Receptors can undergo down regulation and up regulatoin
Description : List several general cellular processes regulated by receptor tyrosine kinases (RTKs).
Last Answer : Cell growth, cell differentiation and cell survival (i.e. nutrient and stress signaling).
Description : Insulin receptor is made up of (A) One α-and one β-subunit (B) Two α-and two β-subunit (C) Two, α two β-and two γ-subunit (D) One α, one β-one γ-and one δ-subunit
Description : β-Subunits of insulin receptor are present (A) Outside the cell membrane (B) In the cell membrane (C) Across the cell membrane (D) In the cytosol
Description : α-Subunits of insulin receptor are present (A) Outside the cell membrane (B) In the cell membrane (C) Across the cell membrane (D) In the cytosol