The purpose of this book is to explore the mesoscale mechanics of the cell: its structure and behavior on length scales of tens of nanometers to microns. This expedition cannot be undertaken without a biochemical lexicon, in part because the mechanical properties of some structures are a direct reflection of their molecular composition, and in part because the text draws constantly from the language of biochemistry. In this appendix, we describe in more detail the nomenclature and composition of several classes of compounds referred to in the main text, including:

For a more thorough treatment of biomolecular building blocks, the reader is directed to books such as Alberts et al. (1994), Gennis (1989), and Lehninger et al. (1993).

Fatty acids and phospholipids

One of the principal constituents of cellular membranes is the family of dual-chain lipids formed from fatty acids, which are carboxylic acids of the form RCOOH, where R represents a long hydrocarbon chain. In cells, fatty acids usually are not found in their free state, but rather are components of covalently bonded molecules such as phospholipids or triglycerides. A major component of cell membranes, phospholipids contain two fatty acids linked to a glycerol backbone.