2.1 CELL STRUCTURE Flashcards
Four types of microscopes
1) light
2) scanning electron
3) transmission electron
4) laser scanning confocal
Define resolution
- minimum distance between two objects in which they can still be seen as separate
Define magnification
- how many times larger the image is compared to the actual object
Formula for magnification
Image = Actual x Magnification
State the 3 steps to calibrate an eye piece graticule
1) line up the stage micrometer and eyepiece graticule whilst looking through the eyepeice
2) count how many divisions on the eyepiece graticule (ruler below) fit into one division of the micrometer scale (ruler above)
3) length of one division on the micrometer (ruler above) DIVIDED BY how many divisions of the eyepiece graticule (ruler below) fit into it
Name the four types of slides/mounts used in light microscopy
1) Dry mount
2) Wet mount
3) Squash slides
4) Smear slides
Describe how dry mounts are prepared
- Place a cover slip on top of specimen
Describe how wet mounts are prepared
- Add water to specimen
- Lower cover slip with mounted needle to prevent air bubble formation
Describe how squash slides are prepared
- Add water to specimen
- Lower cover slip with mounted needle to prevent air bubble formation
- Squash cover slip down to ensure thin enough layer of specimen formed
Describe how smear slides are prepared
- Use edge of another slide to smear sample across the slide to produce even, thin coat
- Place a cover slip on top
Define differential staining
- using many chemical stains to stain different parts of a cell different colours in light microscopy
Why is differential staining important? (2)
- provides increased contrast for differentiation
- to make cells/cell organelles visible
State the relative magnification of all the microscopes
(lowest magnification) Light < LSCM < SEM < TEM (highest magnification)
State the relative resolutions of all the microscopes
(lowest resolution) TEM < SEM < Light < LSCM (highest resolution)
Describe the type of image produced by a Light microscope
- 2D
- Coloured
Describe the type of image produced by a Laser Scanning Confocal microscope
- 2D OR 3D
- Coloured