48. Receptor tyrosine kinases (RTKS) form a large and important class of cell surface receptors whose ligands are soluble or membrane bound protein or peptide hormones. Which of the following […]
47. Binding of erythropoietin to its EPO receptor leads to activation of which signaling pathway? (1) JAK-STAT pathway (2) NF-kß pathway (3) Apaf-Smad pathway (4) Tyrosine kinase pathway Overview of […]
46. With reference to the signaling pathway shown above, which one of the following options correctly identifies the intracellular components? (1) a-Grb2, b-SOS, c=Ras-GTP, d=ERK (2) a=GRB2, b-Ras-GDP. c=MEK, d=ERK […]
45. Which of the following is a component of MAP kinase signal transduction pathway? (1) IP3 (2) ERK (3) Protein Kinase B (4) JAK kinase Introduction The MAP kinase (MAPK) […]
43. The platelet-derived growth factor (PDGF) is a dimer consisting of two identical polypeptides. On binding to its cell surface receptor.it induces dimerization of the receptor by binding to two […]
42. Localized increases in the cytosolic level of free Ca2+ arecritical to its function as second messenger. Calmodulin,a small cytosolic protein, mediates many cellular effectsof Ca2+. Which of the following […]
41. Effect of production of during Signal transduction pathway is (1) Closure of Ca2+ channel in ER (2) Increase in intracellular Ca2+ level (3) Increase of extracellular Ca2+ level (4) […]
40. Release of intracellular calcium is due to (1) absence of PIP2 hydrolysis. (2)rapiddephosphorylation of IP3 (3) retention of DAG in the cytosol. (4) activation of IP3 receptors. Introduction Calcium […]
39. In the context of signaling, the enzyme protein kinase C (PKC) depends on multiple molecules for its complete activation. This activation depends on the presence of: A. phosphatidylserine at […]
38. The cytoplasmic domain of the receptor of which of the following proteins does NOT function as tyrosine kinase? (1) Epidermal growth factor (2) Platelet derived growth factor (3) Insulin […]
