This module builds on the principles of biochemistry taught in BIO-1A14. Selected topics in intermediary metabolism are covered in greater depth and extended to include the specific roles of coenzymes in metabolic pathways. In turn this leads to a discussion of the roles of hormone-receptor interactions and signal transduction in metabolic regulation. The recent contributions of structural biology to cellular biochemistry are acknowledged in both the lecture series and associated practical classes, whilst ATP utilization is illustrated by consideration of the active transport of molecules across membranes in both prokaryotes and eukaryotes.