These macromolecules are polar [polar: having different ends] because they are formed by head to tail condensation of polar monomers. Let's look at the three major classes of macromolecules to see how this works, and let's begin with carbohydrates.
Bostwick Steel Lath Company advertisement for steel truss loop type metal lath in 1920. A lath or slat is a thin, narrow strip of straight-grained wood used under roof shingles or tiles, on lath and plaster walls and ceilings to hold plaster, and in lattice and trellis work.
Mu-metal Mu-metal is a range of nickel-iron alloys that are notable for their high magnetic permeability, composed of approximately 77% nickel, 16% iron, 5% copper and 2% chromium or molybdenum. The high permeability makes mu-metal useful for shielding against static or low-frequency magnetic fields.