Question

Bindicate the CORRECT statements about digestion and the secretory activity of the stomach. 1) the secretion of hydrochloric acid by the parietal cells of gastric glands requires the enzyme carbonio anhydrase 2) the cells of gastric glands secrete digestive enzymes that break down the glycosidio bonds of starch 3) the "intrinsic factor activates the formation of pepsin by pepsinogen 4) the chief cells of gastrio glands synthesize and secrete pepsinogen 5) the chief cells of gastric glands synthesize and secrete pepsin 82 Which of the listed statements about calcitonin is WRONG? it is secreted by the Cools of the thyroid gland the receptors of calcitonin are protein associated membrane receptors it is secreted when the Ca2+ level in blood is low promotes renal excretion of Ca2+the triggered signaling pathway in target cells is CAMP dependent 83. Indicate the correct answers about the structure of elastin. 1) it forms a triple helix 2) it is synthesized as a soluble monomer (tropoelastin) and some proline residues are hydroxylated 3) it is a glycoprotein as there is glycosylation of some of the hydroxyproline residues 4) tropoelastin contains hydroxylated lysine residues (OH-Lys) 5) it does not contain regularly the Gly-X-Y sequences in its chain 84. Which of the following statements are CORRECT? 1) fibrous proteins have polypeptide chains arranged in long strands 2) globular proteins have polypeptide chains folded into a spherical shape 3) most enzymes and regulatory proteins are fibrous 4) globular proteins are insoluble in water 5) fibrous proteins and elastin