Final answer:
The enterocytes in the small intestine absorb amino acids and di/tripeptides through active transport mechanisms. Once these peptides enter the cells, they are broken down into their amino acids and transported out of the cell.
Step-by-step explanation:
The enterocytes in the small intestine absorb amino acids and di/tripeptides through various mechanisms. In the absorptive epithelial cells, active transport mechanisms primarily in the duodenum and jejunum transport most proteins as their breakdown products, amino acids. Short chains of dipeptides or tripeptides can also be actively transported.
Once these peptides enter the absorptive epithelial cells, they are broken down into their amino acids through intracellular proteases. The individual amino acids are then transported out of the cell and enter the capillary blood via diffusion.