When carbohydrates from food are digested, lots of glucose molecules, along with some fructose and galactose, are produced in the small intestine. Initially the mode of transport of glucose in absorption is diffusion. It is then followed by facilitated diffusion via co-transport, where glucose molecules are absorbed along with a sodium ion (Na+) through a carrier protein. This method is much faster than diffusion by itself.

Both Na+ and glucose must be present for absorption by co-transport to take place….