2.1.3 Methods of studying cells

remember IAM in triangle formation for magnification calculations.

Features of a light microscope

light focused using glass lenses
generates a 2D image of a cross-section
Low resolution due to long wavelength of light
Cant see internal structure of organelles
Low magnification (x1500)
can show colour

Features of a Transmission electron microscope (TEM)

electrons focused using electromagnets - electrons pass through specimen, denser parts absorb more and appear darker
generates a 2D image of a cross-section
very high resolution due to short wavelength of electrons
can see internal structures of organelles
high magnification (x1,000,000)
does not show colour

Features of a scanning electron microscope (SEM)

electrons focused using electromagnets - electrons deflected/ bounce off specimen surface
generates a 3D image of surface
high resolution due to short wavelength of electrons
cant see internal structures
high magnification (x1,000,000)
does not show colour

How do you calculate the magnification of a micrograph?

Size of image over size of actual object

How do you calculate the size of the image in a micrograph?

Size of actual object multiplied by magnification

How do you calculate the size of the actual object from a micrograph?

size of image over magnification