This higher tier covers Going Further: Electron Microscopy Higher within Cell Structure for GCSE Biology. Cell theory, prokaryotic and eukaryotic cells, animal and plant cell organelles, bacterial cells, specialized cells, and microscopy It is section 14 of 17 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers 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.
Practice questions for Cell Structure
Which part of the cell contains DNA and controls the cell's activities?
Describe the structure and function of chloroplasts.