Final answer:
Channel proteins are integral proteins permanently embedded within the plasma membrane, creating pathways for specific substances to enter or exit the cell. Unlike peripheral proteins, which can be temporarily associated with the membrane, channel proteins facilitate transport across the membrane's nonpolar central layer.
Step-by-step explanation:
Channel proteins are a specific type of integral proteins that span the entirety of the cellular membrane, creating pathways that allow specific substances to travel in and out of the cell. Unlike peripheral proteins, which are loosely associated and can be found on the membrane's exterior or interior surfaces, integral proteins are embedded within the plasma membrane and often function as channels or transporters. Channel proteins are critical in the facilitation of transport, as they enable polar and charged substances to bypass the nonpolar central layer of the plasma membrane, which would otherwise impede their movement through the cell membrane.
For instance, aquaporins are a type of channel protein that greatly accelerates water movement through the membrane. It's important to understand that despite their vital role in transport, channel proteins do not detach from the membrane-like peripheral proteins, which may temporarily associate with the membrane or with other integral proteins. This permanent embedding in the membrane is a definitive characteristic of integral proteins.