Final answer:
Transport proteins in cell membranes facilitate the passage of polar solutes, with carrier and channel proteins being two main types that enable this transport.
Step-by-step explanation:
Embedded in cell membranes to aid the passage of polar solutes into the cell are transport proteins. These proteins facilitate the movement of ions, polar molecules, and other substances that cannot easily pass through the hydrophobic lipid barrier of the cell membrane. The two main types of transport proteins are carrier proteins and channel proteins. Channel proteins create hydrophilic pathways that enable polar compounds to bypass the membrane's nonpolar central layer. An example of a channel protein is an aquaporin, which allows water to pass through the membrane rapidly.