Final answer:
Channel proteins and aquaporins allow water and solutes to bypass the lipid portion of the cell membrane by providing hydrophilic pathways for these molecules to cross the hydrophobic membrane barrier.
Step-by-step explanation:
The class of membrane proteins that allow water and solutes to bypass the lipid portion of the cell membrane are channel proteins and more specifically known as aquaporins when referring to water transport. These proteins facilitate the movement of polar compounds and ions across the hydrophobic interior of the cell membrane, making it possible for these substances to enter or exit the cell without interacting with the lipids. Aquaporins are specialized channel proteins that enable water to move through the membrane at a high rate, supporting the cell's water balance and homeostasis.