Co transport and absorption

epithelial cells (3)

• absorb glucose and amino acids by co-transport

• line ileum (small intestine) and proximal convoluted tube (in kidney nephron)

• are adapted for absorption

adaptations for cells involved in absorption (2)

• many mitochondria (produce more ATP for active transport)

• membrane is folded to form MICROVILLI (increase surface area, number of carrier proteins in membrane)

Steps of co transport and absorption (3)

1. Na+ / K+ pump

2. Na+ enters cell form lumen by facilitated diffusion through co-transport protein. glucose also enters

3. glucose enters blood through carrier protein by facilitated diffusion

Na + / K + pump (3)

• Na / K pump actively transports Na+ out of epithelial cell into blood, and K+ out of blood

• generates concentration gradient between liken of gut and cell

• by lowering Na+ conc. inside of cell

Step 2 of co transport and absorption (3)

• Na+ enters cell from lumen by facilitated diffusion

• Na+ passes through co transport protein so glucose also enters by facilitated diffusion

• this increases glucose concentration in cell, creating a concentration gradient