The microscope in cell studies
The Microscope in Cell Analysis
- Microscopes allow us to visualise minute biological structures, aiding us in understanding the complexity of cells.
- There are three main types of microscopes used in cell biology: the light microscope, the transmission electron microscope (TEM) and the scanning electron microscope (SEM).
Light Microscope
- The light microscope uses light to illuminate the sample, generating a magnified image on a screen or photographic film.
- It has a relatively low resolution, so it can't resolve smaller structures like individual ribosomes.
- However, it allows for the viewing of living samples and processes over time, like mitosis.
Transmission Electron Microscope (TEM)
- The TEM works by transmitting a beam of electrons through a very thinly sliced specimen.
- TEMs have a high resolution and can magnify up to two million times, revealing minute cellular structures.
- However, they can't be used to image living cells or tissues, as samples have to be fixed, dehydrated, and embedded in resin.
Scanning Electron Microscope (SEM)
- The SEM emits a beam of electrons onto the surface of a specimen causing secondary electrons to bounce off and form a 3D image.
- SEM provides a three-dimensional view of the specimen surface, but with lower resolution compared to TEM.
- Similar to TEM, SEM requires extensive sample preparation rendering the samples unusable for studying live processes.
Electron Microscopy vs Light Microscopy
- Both electron microscopes (TEM & SEM) allow for much higher resolution and magnification than light microscopes, revealing far more cellular detail.
- However, they require more extensive sample preparation and cannot be used to study living specimens.
- Understanding the strengths and weaknesses of each type of microscope allows for their effective use in cell biology.