Final answer:
Nutrients are absorbed at the apical surface of gut epithelial cells through secondary active transport and released through facilitated diffusion at the basal and lateral surfaces.
Step-by-step explanation:
The mechanism that best describes the process by which nutrients are taken up at the apical surface of the epithelial cells lining the gut and released from their basal and lateral surfaces involves several cellular transport methods, mainly secondary active transport (also known as co-transport) and facilitated diffusion.
Nutrients such as glucose are absorbed into epithelial cells of the small intestine via a symport protein that uses the Na+ concentration gradient maintained by Na+/K+ ATPases at the basal membrane. This secondary active transport allows glucose to enter the cell against its own gradient. After entering the epithelial cells, these nutrients are then moved out of the cell's basal side into the interstitial fluid and into blood capillaries by facilitated diffusion, a process that does not require direct energy (ATP) but relies on specific transport proteins.
Other transportation methods involved in this process include active transport, passive diffusion, and endocytosis. However, the symport mechanism coupled with facilitated diffusion is key for the efficient uptake and subsequent release of water-soluble nutrients across epithelial cell membranes in the gut.