Microscopy
Microscopy enables us to see what cells look like
Magnification – is how much bigger something looks
Resolution – the ability to see two adjacent but separate points as distinct entities following magnification. A higher
resolution means that detail can be seen more clearly.
Units of Microscopes
Unit Symbol Size in metres
millimetre mm 10-3
micrometre μm 10-6
nanometre nm 10-9
Light Microscope
Used in classrooms
The resolving power of the light microscope is limited by the small range of light wavelengths
Slide is often stained to make the cell, or specific structures inside the cell, more visible.
Iodine and methylene blue are two stains sometimes used
Advantages Disadvantages
Living specimens can be observed. This means that Low resolving power
biological processes can be observed using LM
Ease of Use-Is portable and the preparation of the Only allows macrostructure to be viewed so the
slides is much easier than for EM smallest organelles cannot be viewed
Allows colour to be seen
Much cheaper than EM
Electron Microscope
This type of microscope uses electrons rather than light to produce images
EM have a much greater resolving power compared to light microscopes
This is because electrons have a much shorter wavelength compared to light.
There are two types of EM:
Transmission Electron Microscope:
Electrons are passed through a very thin specimen. Images produced have a very high resolution and can be
magnified greatly
Microscopy enables us to see what cells look like
Magnification – is how much bigger something looks
Resolution – the ability to see two adjacent but separate points as distinct entities following magnification. A higher
resolution means that detail can be seen more clearly.
Units of Microscopes
Unit Symbol Size in metres
millimetre mm 10-3
micrometre μm 10-6
nanometre nm 10-9
Light Microscope
Used in classrooms
The resolving power of the light microscope is limited by the small range of light wavelengths
Slide is often stained to make the cell, or specific structures inside the cell, more visible.
Iodine and methylene blue are two stains sometimes used
Advantages Disadvantages
Living specimens can be observed. This means that Low resolving power
biological processes can be observed using LM
Ease of Use-Is portable and the preparation of the Only allows macrostructure to be viewed so the
slides is much easier than for EM smallest organelles cannot be viewed
Allows colour to be seen
Much cheaper than EM
Electron Microscope
This type of microscope uses electrons rather than light to produce images
EM have a much greater resolving power compared to light microscopes
This is because electrons have a much shorter wavelength compared to light.
There are two types of EM:
Transmission Electron Microscope:
Electrons are passed through a very thin specimen. Images produced have a very high resolution and can be
magnified greatly
