Rights: Tomographic images by T. Frey (SDSU) and G. Perkins (UCSD); with the permission of Professor Frey .TEM micrograph released into Public Domain. Published 29 February 2012 Size: 310 KB

Microscopes have been crucial for our understanding of mitochondrial structure and function. Mitochondria are visible under the light microscope although little detail can be seen. Transmission electron microscopy (left) shows the complex internal membrane structure of mitochondria, and electron tomography (right) gives a three-dimensional view.