According to the characteristics of higher vocational education , the book focuses on the basic knowledge of simple sugars, lipids, nucleic acids, proteins, enzymes , vitamins , metabolism, glucose metabolism , lipid metabolism , protein degradation and amino acid metabolism , nucleotide metabolism , DNA replication and RNA biosynthesis and processing , protein biosynthesis , the basic theory of the metabolic regulatory network. Some chapters in the back of the book are equiped with experiment .