More than one type of proton pump ptype atpas. Epithelial cells have epithelial polarity top of picture microvilli, to increase sa, reaching into lumen of intestine on apical side of cell lateral domains down the sides; basal domains. Important to have a barrier to control what comes in and out of lumen transport proteins on apical side decide what comes in and what doesn"t selective process. Tight junction thus do not pass between the cells nothing can pass in between even water cannot move cell decides what moves. 7 green proteins do not move down to basallateral domain proteins can move lateral but cannot move past tight junction. 8 more glucose in cytosol than lumen of epithelial so glucose will move down concentration gradient. Symporter two molecules moved in same direction. Passive transport of glucose through glut2 uniporter glucose escapes cell into interstitial fluid passively.