Microscopes & Cultures - Microscopes (GCSE Biology)

Microscopes

Cells can be seen with microscopes. Microscopes magnify small things that can’t usually be seen by the naked eye. This allows us to view cells within organisms
Light microscopes were created first. Light microscopes have a magnification power of up to x2000. They use the beams of light and lenses in order to magnify a living object to create an image. They are cheap and portable and can be used to see cells and large organelles, or sub-cellular structures, such as nuclei.
Electron microscopes changed the field of biology. Electron microscopes have a much higher magnifying power than light microscopes, and so could be used to see more sub-cellular structures, improving our understanding of biology.

Resolution is the ability to tell the difference between two points. The greater the resolution of a microscope, the more detailed the image. In an image with a low resolution, two nearby objects may look like one.
Magnification is the size of the image compared to the real size of the object. Magnification tells you how big an image is compared to the real object.
Both resolution and magnification are important. Resolution is a key factor in the quality of an image taken by a microscope, whilst magnification determines the objects you can see. The higher the magnification of the microscope, the smaller the object that can be seen through it.

Covering every topic in the GCSE syllabus

Electron microscopes have a higher magnification. Electron microscopes provide a more magnified image than a light microscope. Electron microscopes use beams of electrons to make a magnified image. They have the magnifying power of around x2,000,0000.
Electron microscopes also have a higher resolution. Electron microscopes also have a higher resolution, so provide a sharper image.
But electron microscopes have drawbacks. However, electron microscopes are huge machines and are expensive, as they require specific operating conditions. Moreover, they can only be used to view non-living cells.

Main parts of a light microscope you should be familiar with:

Microscope slide – a clear plastic/ glass piece on which you mount your specimen being investigated
Cover slip – this is a square clear plastic/ glass piece which goes on top of your specimen
Stage – this is where you clip your microscope slide into place
Eyepiece lens – this is the part of the microscope you look through
Objective lens – these magnify the image and there are different types with different magnification levels
Lamp – this shines light to the specimen so it can be seen more clearly
Coarse/ Fine adjustment knobs – these help focus the image so it is clearer