Going Further: Electron Microscopy Higher

🔭 Going Further: Electron Microscopy Higher

Light microscopes use visible light, which limits their resolution to about 200 nm — meaning structures smaller than this appear blurred. Electron microscopes use beams of electrons instead of light. Because electrons have a much shorter wavelength than visible light, they can resolve structures as small as 0.1 nm.

There are two main types. A Transmission Electron Microscope (TEM) fires electrons through a thin slice of specimen, revealing internal structures in extraordinary detail — including the endoplasmic reticulum, Golgi apparatus, and the inner membranes of mitochondria and chloroplasts. A Scanning Electron Microscope (SEM) bounces electrons off the surface of a specimen, producing detailed 3D images of the outside of cells and organelles.

Electron microscopes must be used in a vacuum and cannot be used with living specimens, but they revolutionised our understanding of cell ultrastructure.