Microscopes And Magnification Flashcards
Why are microscopes useful?
Can see cell structures/processes
Can see things you can’t with the naked eye
Increase our understanding at a sub-cellular level
Diagnostic tool
Develop vaccines and cure
What is the definition of magnification?
The act of process or enlarging the physical appearance or image of something
What is the definition of resolution?
The minimum distance apart from 2 objects can be in order to appear as separate items
What are the different types of microscopes?
Light
Scanning electron
Transmission electron
What is the source, magnification, resolution, sample preparation and resulting images of a light microscope?
Light X1500 Poor resolution Washed, stained, covered Less detailed images
What is the source, magnification, resolution, sample preparation and resulting images of a SEM
Electron X20000 High (20nm apart) Coat surface with thin layer of gold 3D images produced
What is the source, magnification, resolution, sample preparation and resulting images of a TEM
Electron X500000 Highest (0.1nm apart) Sliced and stained with heavy metal 2D Black and white images
What are the disadvantages of a light microscope?
Cannot see small cells, organelle or virus
What is a disadvantage of SEM
Must be in a vacuum
What is a disadvantage of a TEM
2D Black and white images
What is an artefact?
Something seen that is not naturally present
What are the problems with artefacts?
Creates uncertainty about structures apparently seen
May include wrinkles in the cells
Gives the appearance of structures which are not there
What are the main parts of a microscope?
Eyepiece lens Arm Stages Mirror/light source Focus adjuster Objective lens Base
What are the hazards with microscopes?
Broken glass
Light
Electrical devices
What is the equation for magnification?
Size of image over size of real object
