Microscopes

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Microscopes magnification
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Light microscope

• Observation of living cells
• Wide range of magnifications 40-400X
• Easy to use maintain
• Portable
• Allows for a larger field of view due to its
  lower magnification
• Sufficient resolution for viewing cells and SOME
  organelles

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Electron Microscopes

• Higher magnification up to 500,000X
• Higher resolution around 1 nanometer
• Resolution ability to determine two points as
  separate
• Two types
• TEM transmission electron microscope
• SEM scanning electron microscope

TEM
SEM
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TEM

• Highly detailed
• 2-D images
• Electrons are passed through the image
• Uses electromagnets

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SEM

• 3-D images
• Specimen are coated with metal and electrons are
  scanned back-and-forth

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Size comparison
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Size comparison
Structure Measurements
Molecules 0.5 1 nm
Membranes 10 15 nm
Viruses 50 200 nm
Bacteria 5 10 µm
Organelles 5 10 µm
Cells 10 100 µm
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Calculating magnification

• Drawings and photographs are often enlarged.
• To calculate magnification, use this formula
• magnification size of image/size of specimen
• The calculate the actual size of the specimen,
  you need to know the size of the field vision.
  This can be done using a micrometer or ruler

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Calculating magnification

• This mitochondrion is magnified 300,000x. It has
  an actual size of 5.6 nm. Calculate the size of
  the image.

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Any Questions??