3-1 looking at cells ppt
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DESCRIPTIONThis presentation correltates to section 3-1 of Holt Biology ed. 2004
- 1. Section 3-1 Heather Sullivan- FRHSD
- Describ e 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.
- Low Power (LP)= 40x
- Image seen
- Field of view
- Specimen can still be alive
- Fairly inexpensive
- 6. Pine Pollen 2000x
- Shoots a beam of electrons through a specimen to illuminate it
- Must be in a vacuum so electrons dont bounce off air molecules
- Cant study living cells
- Can study cell details & cell surface
- Creates 3-D image
- 8. Hibiscus Pollen 200,000x
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