microscopes xx Flashcards
(16 cards)
what are light microscope characteristics?
- 2 lenses
- usually illuminated underneath
- max magnif of 2000x and rp 200mn
- lower rp more detail
- used to view tissues, cells and large sub cellular structures
- cells of cork absorbed by robert hooke in 1665
what are electron microscope characteristics?
- can see organelles more clearly - especially very small structures e.g. nucleus
- electrons used to from an image because electrons have much smaller wavelength than that of light waves
- scanning electron microscope (2,000,000x mag, 10nm rp) - created 3D image
- transmission electron microscope (2,000,000x mag, 0.2nm rp) - created 2D image
what are TEM microscopes used for?
to discover viruses such as ebola, smallpox and poliovirus
what are electron microscopes used to examine?
proteins in greater detail, led to many scientific discoveries
whats magnification of light microscope equation?
magnif of eyepiece x magnif of objective lens
what’s size of object equation?
size of image / magnif
what’s the eyepiece?
part we look through
what’s the barrel?
mixed up or down to focus image
what’s the turret?
rotated to change magnif lens in use
what’s the lens?
lens increases magnification of specimen
whats stage?
flat surface where we place specimen
how to use light microscope?
- place slide on stage an shook through lens
- turn focus wheel for clear image
- start with lowest objective lens magnification
- increases magnification objective lens
what’s the 1st practical stage?
- take thin layer of cells from sample by peeling or cotton bud
whats 2nd stage of practical?
add iodine solution to make some parts more visible
whats 3rd stage of practical?
add cells to glass slides
whats 4th stage of practical?
carefully lower a coverslip, try to avoid air bubbles
