This class targets students with entry-level background in cell biology. It serves as refreshment as well as a boost course for those aiming to major in all disciplines in biology. The class starts with defining the main terminology and fundamental principles of cell biology, it then recapitulates the different building blocks of cells from molecular to organelle level. Using a combination of upfront classroom teaching and problem-based learning, the principles of signaling, metabolism and energy homeostasis are discussed in the context of cellular organization.