Chapter 9: Cell Membrane and Transport Mechanisms
Learning Objectives
By the end of this chapter, you will be able to:
- Describe the structure and function of the cell membrane, including its regulation of materials into and out of the cell.

The plasma membrane, the cell membrane, has many functions, but the most basic one is to define the cell’s borders and keep the cell functional. The plasma membrane is selectively permeable. This means that the membrane allows some materials to freely enter or leave the cell, while other materials cannot move freely, but require a specialized structure, and occasionally, even energy investment for crossing.
License and attributions:
- Biology, Second edition, 2018, Clark, M.A. et al. License: CC BY 4.0. Located at https://openstax.org/books/biology-2e/pages/5-introduction