analysis of cell components
- Created by: Margaret Hobart
- Created on: 02-05-21 13:54
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- analysis of cell components
- optical (light) microscopes
- use light to form an image
- have a maximum resolution of 0.2Mm
- can't see ribosomes, endoplasmic reticulum or lysosomes
- maximum magnificationof x1500
- electron microscopes
- use e- to form an image
- higher resolution than optical microscopes so give a more detailed image
- maximum resolution of 0.0002Mm
- maximum useful magnifications x1500000
- transmission electron microscope (TEMs)
- use electromagnets
- denser parts absorb more e- so look darker
- only used on thin specimens
- flat and 2D
- Scanning electron microscope (SEMs)
- beam e- across specimen
- this knocks off e- from the specimen which are gathered in a cathode ray tube to form an image
- surface of specimen, 3D
- lower resolution than TEMs
- beam e- across specimen
- magnification=image size/object size
- image= appearance on microscope
- cell fractionation
- 1. get a sample of tissue the same concentrationas inside the cells
- isotonic solution
- stops osmosis so organelles don't burst
- ice cold to stop enzyme activity
- buffer to stop pH changes
- 2. grind tissue in blender to break up cells
- homogenisation - a sample with all contents distributed evenly
- 3. fileter to remove insoluble tissue e.g. cel wall
- 4. centrifuge sample
- spin at low speeds and gradually get faster
- low speeds = heaviest organelles in pellet
- Untitled
- re-spin supernatant
- low speeds = heaviest organelles in pellet
- spin at low speeds and gradually get faster
- 4. centrifuge sample
- isotonic solution
- 1. get a sample of tissue the same concentrationas inside the cells
- optical (light) microscopes
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