ABSTRACT
The field of biology can be summarised as the study of cells and the ways they interact. Across the natural world, these cells – the fundamental building blocks of life – show great variance, differing in size, shape, and function. However, one feature that is consistently present across all cell types is the plasma membrane: this is the barrier that separates the aqueous compartment that forms the cell’s interior from its surrounding extracellular environment. The full extent of the plasma membrane’s function has still not yet been fully mapped, but it is known to be essential for maintaining cell structure and therefore cell survival. Additionally, the membrane is paramount for conducting cell–cell communication, regulating the ingress and egress of ions and molecules into and out of the cell, and regulating interactions with the surrounding medium, such as adhesion. Due to their importance, plasma membranes are a frequent area of study in the biological sciences, and a myriad of techniques have been deployed to understand their composition, structure, and function. These range from biochemical methods, NMR, mass-spectrometry, and atomic force, electron, and optical microscopy to name but a few. Fluorescence microscopy, due to its molecular specificity and minimal invasiveness, is often the tool of choice for studying live cells and is a mainstay of biological research the world over. This section will explore the general composition and structure of plasma membranes, and the design and function of base-line fluorescence microscopy techniques that can be used for their study.
