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STUDYING CELLS
MAGNIFICATION

Magnification- How large the image is compared to real life
Magnification can be calculated with this:

The unit of measurements are: nanometer, micrometer, millimeter

1000

1000
micrometre

1000

Nanometre (nm)

1000

Micrometre (μm)

Millimetre mm

5

0
...
000005

1 000 000

1000

1

MICROSCOPES
LIGHT MICROSCOPE (LM)/ OPTICAL MICROSCOPE





Used in labs- e
...
onion cells
Magnification x 1500
Resolution 200nm
Uses light rays and several lenses



Cannot view very small things (resolution and magnification are too low because the
wavelength of light is too large)
 Inexpensive
 Can view a variety of samples

ELECTRON MICROSCOPES


Generates a beam of electrons (Have a shorter wavelength so a greater resolution)

SCANNING ELECTRON MICROSCOPE (SEM)


Electrons reflected of surface
 Magnification x 100 000
 3D image produced – because electrons bounce off specimen

TRASMISSION ELECTRON MICROSCOPE (TEM)





Magnification x 500 000
Electrons pass through thin sample
2D image produced
Lots of preparation of the samples

Resolution – Amount of information that can be seen in the image
Cell-Basic unit of an organism= cytoplasm- jelly like substance, cell membrane

CELL FRACTIONATION/HOMOGENIZATION & ULTRACENTRIFUGATION
Fractionation- breakup
Ultracentrifugation- spinning

This separates the
cells into parts we
can study

Centrifuge

1
...
ALSO TEMPERATUE MUST BE LOW- (prevents the action of enzymes which
would damage the tissue - place the beaker in iced water then chop up the tissue into smaller
pieces with the knife)

2
...
This creates
a homogenate
...
Filter off the debris of the homogenate
4
...
The centrifuge is spun at low speed
...
E
...
(nucleus, nuclei)
6
...
Mitochondria collected
(The liquid)
7
...
The tiniest organelles collected
(Ribosomes)

Pellet containing nucleus

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