Analysis of cell components

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  • Created by: samya_
  • Created on: 27-12-17 15:01
What is the equation for magnification?
Size of image divided by size of real object
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How many mm is 1 micrometer
O.oo1 mum therefore to convert from micrometers to mm you need to divide by 1000
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Differences between optical microscope and electron microscope?
Optical: uses light, colour image, specimen can be alive/moving, portable and easy to use without training ELECTRON: uses electron to from image, black+white, complex practice/ skilled technician, specimens must be ded since placed in vacuum hit res
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How do TEMs work?
TEMs use electromagnets to focus a beam of electrons, which is then transmitted thrkught the specimen , denser part of lseicmen absorb more electrons, which makes them look darker on image you end up with
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How do SEMs work?
SEMs scan a beam of electro runs across the specimen. This knocks off electrons form the specimen, which are gathered in a cathode ray tube to form an image
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Differences between TEMs and SEMs
TEMs: give high resolution, so you see internal structure of organelles.. can only be used on thin species SEMs: images you end up with show the surface of specimen , can be 3D , can be used on thick specimens, give lower resolutions than TEMs
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How to prepare a "temporary mount"
1) start by pipette for small drop of water on slide, then use tweezers to place thin section of specimen on top of water drop 2) add a drop of stain to highlight the objects in organelle 3) finally add cover lip, try not to get any air bubbles
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First step of Cell Fractionation, HOMOGENISATION? Breaking up cell
This can be done several ways, vibrating the cells/grinding the cells in a blender(homogeniser) . This breaks plasma membrane and releases organelles into solution
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What 3 things mus they solution be and WHY?
Ice cold- reduce activity of enzymes that break down ornganeels, ISOTONIC- same conc of chemicals as cell being broken down BUFFER SOLTUION- to maintain pH
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Second Step of Cell fractionation? Filtration
Homogenate filtered thrkught gauze to seperage large cell debris/ tissue debris
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Third FINAL STEP? Ultracentrifugation? Sepreating orgnaelles
Cell fragments poured into tube then centrifuge and spun at low speed. Heaviest organelles flung to bottom of tube and form thick sediment(pellet) above sediment is called the supernatant,.drained+ poure- process repeated at higher and higher speeds
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Other cards in this set

Card 2

Front

How many mm is 1 micrometer

Back

O.oo1 mum therefore to convert from micrometers to mm you need to divide by 1000

Card 3

Front

Differences between optical microscope and electron microscope?

Back

Preview of the front of card 3

Card 4

Front

How do TEMs work?

Back

Preview of the front of card 4

Card 5

Front

How do SEMs work?

Back

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