Amphiphatic helices are

Many α helices have predominantly hydrophobic R-groups projecting from one side of the axis of the helix and predominantly hydrophilic R-groups projecting from the other side. These amphipathic helices are well adapted to the formation of interfaces between polar and nonpolar regions such as the hydrophobic interior of a protein and its aqueous environment. Clusters of amphipathic helices can create channels, or pores, through hydrophobic cell membranes that permit specific polar molecules to pass. Note: Clusters of twisted strands of β sheet are called β barrels. Ref: Harper’s illustrated biochemistry. 30th edition page no: 37