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.
Lath seen from the back with brown coat oozing through. Lath and plaster is a building process used to finish mainly interior walls and ceilings in Canada and the United States until the late 1950s.After the 1950s, drywall began to replace the lath and plaster process in the United States.In the United Kingdom and its colonies, lath and plaster was often used for interior partition walls and the construction of ceilings, before the introduction of plasterboard in the 1930s.fter the plaster is completely dry, the walls are ready to be painted. In this article's photo (lath seen from the back...) the curls of plaster are called keys and are necessary to keep the plaster on the lath.