A comprehensive, up--to--date treatment of the biochemistry essential for an understanding of molecular and cellular biological processes. This third edition offers new units covering the chemistry of life, bioenergetics, energy transfer molecules, regulation of enzymes and reaction sequences, lab techniques for purification of proteins and nucleic acids, and lab techniques of molecular genetics. Also, each unit contains more applications to biological systems. The text provides a well--organized and rigorous approach suitable for classroom use or self--instruction. Each unit begins with a 1-- to 2--page presentation of basic concepts, followed by about 20 questions and problems with sample responses. Self--tests appear after every 2 to 3 units and there is a cumulative self--test at the end of the book.