How dissimilar are intracellular and extracellular digestion? What is the evolutionary benefit of extracellular digestion?
Intracellular digestion is that in which the breaking down of macromolecules takes place within the cell. Extracellular digestion is that in which macromolecules are broken down in places outside the cell (in the extracellular space, in the surrounds, in the lumen of digestive tubes, etc.)
The advent of extracellular digestion in evolution permitted organisms to benefit from a greater several of food. The breaking down of larger molecules into smaller ones outside the cell allowed the use of other foods than those that, because of the size of their molecules, could not be interiorized by diffusion, pinocytosis or phagocytosis.