The purpose of the course is to provide a mechanistic understanding of biochemical reactions in terms of organic chemical knowledge. Thus, this course is intended for students with a strong background in organic chemistry, obtained in our third-year courses, CHM347 (organic chemistry of biological compounds) and CHM348 (organic reaction mechanisms). Much of this course is on understanding biological catalysis. Select coenzyme and enzyme catalysis will be discussed focusing on kinetics and mechanisms. This will also include enzyme inhibition and drug design. Other biological applications in molecular recognition and catalysis will be discussed through modern topics in catalytic antibodies, ribozymes, directed molecularevolution, mRNA vaccines, DNA encoded combinatorial libraries (DEL), and base editing and prime editing with CRISPR.