Scientists from the University of Geneva (UNIGE), in collaboration with the Institut de biologie structurale de Grenoble (IBS) and the University of Fribourg (UNIFR), have used cryo-electron ...

and the University of Fribourg (UNIFR), have used cryo-electron microscopy to observe how lipids and proteins at the plasma ...

There are three types of pathways: Caveolae are small invaginations of the cell's plasma membrane. Under the electron microscope, caveolae look to be flask-shape pits about 50-80 nm across.

(lower left) Scanning electron micrograph of titania through-hole membrane. (lower right) Cross-sectional scanning electron micrograph of through-hole membrane. Disclaimer: AAAS and EurekAlert!