This tutorial is designed to familiarize the student with the structure and function of cellular membranes. Cellular membranes are dynamic structures, which define the cell or segregate essential cellular functions. The structure of the cellular membranes will be studied as it relates to the function of the membranes. The readings, problem sets, and case studies will provide the basis for an in depth understanding of (1) the role of the plasma membrane in maintaining homeostasis and communication, (2) the role of organelle membranes for the function of these organelles, (3) the techniques used in the scientific community to investigate the cellular membranes and their components, and (4) enhanced written and oral communication skills. This tutorial is designed to prepare the student for the membranes comprehensive examination; however in the process of presenting an inclusive pictures of cellular membranes the student will study topics also presented in the cytoskeleton, enzyme, and cellular metabolism tutorials. Although this tutorial will concentrate on cellular membranes it is intricately linked with the OXS 465 tutorial that studies the biochemistry of macromolecules. There will be combined assignments for these two tutorials to enhance the integration of knowledge acquired by the students.