BIOL130 Study Guide - Quiz Guide: Active Transport, Endomembrane System, Start Codon
13 Nov 2016
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Biology : face to face oral assignment answers. You are an amino acid in the lumen of the small intestine from a recently digested protein meal, faced with a wall of intestinal epithelial cells. You have always been intrigued by the idea that cells had their own digestive systems. Your ambition is to be incorporated into a lysosomal enzyme within one of those intestinal epithelial cells. Amino acids are uncharged but polar due to the n and c terminus as well as the r group which usually (but not always) also has partial positive or negative charges and is therefore polar. Large polar molecules cannot diffuse through the membrane - amino acids use coupled transport (exactly like glucose) to enter epithelial cells. The apical surface of the intestinal cell has active carriers which carry amino acids (against their gradient) into the cell along with sodium (na) which acts as the cotransport ion and enters down its gradient (secondary active).
