Microscopes (from powerpoint) Flashcards
What is the purpose of staining?
Stains make stuctures visible/ increase contrast.
So you can see different organelles/ recognise different types of cells.
What are the 2 types of stains?
General stains and differentiated stains.
What are differentiated stains?
Stains that bind to specific cell structures, staining each differently so they can be easily identified within a single preparation.
What is methylene blue?
An all purpose stain (blue)
What is Sudan red?
Differentiated stain Lipid stain (red)
What is iodine?
Differentiated stain
Starch-blue/black
Cellulose- yellow
What is magnification?
How many times bigger the image is compared to the actual size.
What is resolution?
The minimum distance apart 2 objects must be in order for them to appear as seperate items.
(better resolution = clearer image)
What is the type of beam in a light microscope?
Light
What is the type of beam in a laser scaning (confocal) light microscope?
Laser light
What is the type of beam in an electron scanning microscope?
Electron
What is the type of beam in an electron transmission light microscope?
Electron
What is the wavelength of a beam in a light microscope?
400-700nm
What is the wavelength of a beam in a laser scanning (confocal) microscope?
400-700nm
What is the wavelength of a beam in an electron scanning microscope?
0.004nm
What is the wavelength of a beam in an electron transmission microscope?
0.004nm
What is the magnification in a light microscope?
x1500-x2000
What is the magnification in a laser scanning (confocal) microscope?
x1500 - x2000
What is the magnification is a electron scanning microscope?
x100,000 - x500,000
What is the magnification in a transmission electron microscope?
x500,000 - x2,000,000
What is the resolution of a light microscope?
200nm
What is the resolution of a laser scanning (confocal) microscope?
800nm
What is the resolution of an electron scanning microscope?
3-10nm
What is the resolution of an electron transmission microscope?
0.2-0.5nm
How are specimens prepared for a light microscope?
Place on glass slide
How are specimens prepared for a laser scanning (confocal) microscope?
Specimen can be tagged with fluorescent dye
How are specimens prepared for a electron scanning microscope?
Speciemen coated with fine layer of metal
How are speciens prepared for a electron transmission microscope?
Thinly spiced, chemically fixed by dehydration and stained.
What image is produced from a light microscope?
2D colour image
What image is produced by a laser scanning (confocal) microscope?
3D image
What image is produced by a electron scanning microscope?
3D image with false colour
What image is produced by a electron transmission microscope?
2D grey scale image
Can a light microscope be used to view living organisms?
Yes
Can a laser scanning (confocal) microscope be used to view living organisims?
Yes
Can an electron scanning microscope be used to view living organisms?
No
Can an electron transmission microscope be used to view living organisms?
No
What is the special viewing condition for electron microscopes?
Viewed in a vacuum, stained with metal salts.
