2.1.3 methods of studying cells (not complete)

What is magnification

The number of times greater the image is than the actual size

What is resolution

Minimum distance apart 2 objects can be to be distinguished as separate objects

Optical, transmission electron or scanning electron: light focused using glass lenses

Optical

Optical, transmission electron or scanning electron: electrons focused using electromagnets

Transmission electron

Scanning electron

Optical, transmission electron or scanning electron: light passes through specific, different structures absorb different wavelengths

Optical

Optical, transmission electron or scanning electron: electrons pass through specimen, denser parts absorb more and appear darker

Transmission electron

Optical, transmission electron or scanning electron: electrons deflected/ bounce off specimen surface

Scanning electron

Optical, transmission electron or scanning electron: generates a 2D image of a cross section

Optical

transmission electron

Optical, transmission electron or scanning electron: generates a 3D image of surface

Scanning

Optical, transmission electron or scanning electron: low resolution due to long wavelength of light

Optical

Optical, transmission electron or scanning electron: very high resolution due to short wavelength of electrons

Transmission electron

Optical, transmission electron or scanning electron: high resolution due to short wavelength of electrons

Scanning electron

Optical, transmission electron or scanning electron: can’t see internal structures

Optical

Scanning electron

Optical, transmission electron or scanning electron: can see internal structures

Transmission

Optical, transmission electron or scanning electron: specimen is thin/ very thin

Thin= optical

Very thin= transmission electron

Optical, transmission electron or scanning electron: Specimen does not need to be thin

Scanning electron

Optical, transmission electron or scanning electron: low magnification = x1500

Optical

Optical, transmission electron or scanning electron: high magnification = x1,000,000

Transmission electron

Scanning electron

Optical, transmission electron or scanning electron: can view living organisms

Optical

Optical, transmission electron or scanning electron: can only view dead/ dehydrated specimens as uses a vacuum

Transmission electron

Scanning electron

Optical, transmission electron or scanning electron: simple preparation

Optical

Optical, transmission electron or scanning electron: complex preparation so artefacts often present

Transmission electron

Scanning electron

Optical, transmission electron or scanning electron: can show colour

Optical

Optical, transmission electron or scanning electron: does not show colour

Transmission electron

Scanning electron

How to calculate magnification

Magnification = image ➗ actual

How to convert between units

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