chemical building blocks from which our cells,
organs, and tissues like muscle are made of. Proteins also serve double-duty
as hormones, enzymes
and antibodies, which help our bodies fight off invading germs. Proteins are
made of long chains of even smaller building blocks called amino acids. Amino acids
determine the size, shape, and length of protein molecules.
They also give protein molecules
the odd ability to coil and uncoil like tiny, cellular snakes.