In this episode, Xavier Bonilla has a dialogue with Siddhartha Mukherjee about cellular biology. They define what a cell is and talk about the importance of Leeuwenhoek and Hooke in observing and discovering the cell. They talk about the five basic principles of cell biology and explore the anatomy of a cell. They explain how important B cells and T cells are for the innate immune system and the adaptive immune system for fighting diseases such as SARS-CoV-2 and HIV. They also talk about the potential of stem cells for human medicine and many other topics.