Microscopy Revision Carousel Flashcards
What are the maximum resolutions of the different microscopes?
Light=200nm
SEM=10nm
TEM=0.2nm
What is a stage micrometer?
A mm long rules etched onto a slide
-100 divisions each of 0.01 mm
Used to calibrate the eyepiece graticule
What is magnification?
A measure of how much larger the image of a specimen looks under the microscope
What is an eye piece graticule?
-A small ruler fitted to a light microscope’s eyepiece.
-Must be calibrates using a stage micrometer before being used to measure specimens
What are the pros and cons of using a light microscope?
Pros-cheap, portable, easy to use, can view live specimens
Cons-limited magnification, poor resolution
What is differential staining?
Using a stain to distinguish between either 2 different organisms or between organelles of a specimen due to preferential absorption of stain
What is the formula to calculate magnification?
Magnification=Image Size/Actual Size
What is the difference between a transmission and a scanning electron microscope?
-TEM sends a beam of electrons through the specimen
-SEM bounces off the surface
What is a laser scanning confocal microscope used for?
Creating a high resolution, high contrast image, at different depths of the specimen
How do we work out image size?
Use a ruler and measure the image
What is a transmission electron microscope used for?
Observing the internal ultrastructure of cells under high magnification and resolution
Why do we stain specimens?
To provide more contrast and make it easier to distinguish certain parts
What is the difference between light and electron microscopes?
-Light uses lenses to focus a beam of light
-Electron uses a beam of electrons, focused by magnets
What are the pros and cons of an electron microscope?
Pros-very high magnification and very good resolution
Cons-specimen has to be dead, expensive, very large and needs alot of training and skill to use
What is resolution?
The ability to distinguish between 2 adjacent individual points as separate
