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.
noun, plural laths. [lath z, laths, lahth z, lahths] /lÃ¦Ã°z, lÃ¦Î¸s, lÉÃ°z, lÉÎ¸s/ (Show IPA) 1. a thin, narrow strip of wood, used with other strips to form latticework, a backing for plaster or stucco, a support for slates and other roofing materials, etc. 2. a group or quantity of such strips. 3. work consisting of such strips. 4. wire mesh or the like used in place of wooden laths as a backing for plasterwork.