3-1 Looking At Cells Ppt
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Transcript of 3-1 Looking At Cells Ppt
Section 3-1
Heather Sullivan- FRHSDHeather Sullivan- FRHSD
Describe how scientists measure the length of objects.
Relate Magnification & Resolution in the use of microscopes
Analyze how a light microscope functions
Compare a Light Microscope with an Electron Microscope
Measuring Cell Structures Scientists use the metric system to measure
the sizes of objects viewed under a microscope.
Characteristics of Microscopes enable biologists to examine the details of cell
structure and to understand how organisms function. Magnification and resolution are two quantitative characteristics of microscopes.
Compound Light Microscope Light microscopes have a low magnification and
can be used to examine living cells.
Electron Microscopes Electron microscopes have a high magnification
but cannot be used to examine living cells.
Scanning Tunneling Microscope The scanning tunneling microscope uses a
computer to generate a three-dimensional image of the object.
Magnification Low Power (LP)= 40x MP=100x HP=400x
Micrograph Image seen
FOV Field of view
Benefits Specimen can still be alive Fairly inexpensive
Pine Pollen 2000x
Shoots a beam of electrons through a specimen to illuminate it
Must be in a vacuum so electrons don’t bounce off air molecules
Can’t study living cells
Benefits Can study cell details &
cell surface Creates 3-D image
Hibiscus Pollen 200,000x