Microscopes
- Created by: jessicawarren
- Created on: 05-04-16 14:23
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- Microscopes
- Magnification/ resolution
- Magnification= Image size\Actual size
- Resolution: how well microscope distinguishes between two objects close together
- Optical (light) microscope
- Use light to form image
- Max resolution of 0.2 micrometers
- Can't see ribosomes, ER, lysosomes
- Magnification of x1500
- Cheap, easy to use, portable
- TEM
- Use electromagnets to focus beam of electrons which is transmitted through specimen
- Denser parts of specimen absorb more electrons and look darker
- High resolution images, can see internal structure of organelles
- Can only be used on thin specimens
- SEM
- Scan a beam of electrons across specimen, Knocks off electrons from specimen
- Images show surface of specimen, can be 3D
- Can be used on thick specimens, lower resolution images
- Large, very expensive, need skill and training to use
- TEM
- Use electromagnets to focus beam of electrons which is transmitted through specimen
- Denser parts of specimen absorb more electrons and look darker
- High resolution images, can see internal structure of organelles
- Can only be used on thin specimens
- TEM
- Preparing a slide
- 1: Pipette a small drop of water onto a slide. Use tweezers to place thin section of specimen on top of water
- 2: Add a drop of stain to highlight objects in cell
- 3: Add cover slip to slide
- Laser Scanning Microscopes
- use laser light to scan object point by point and assemble image by computer
- Images high resolution and high contrast
- Depth selectivity- can focus on structures at different depths within specimen, can be used to observe whole specimens as well as cells
- Used in medical profession to give swift diagnosis and more effective treatment. Also used in biological research
- Magnification/ resolution
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