Microscopy 2.1 Flashcards
Dry mount
solid specimen with cover slip on top
Wet mount
liquid specimen on the slide and place cover slip at an angle
Squash mount
wet mount prepared first then cover slip used to squash specimen
Smear slide
edge of the slide is used to smear the specimen and create a thin even layer
Gram staining technique
used to separate bacteria into two groups: gram positive and gram negative. First the sample will be dyed with crystalline violet which will stain the gram positive bacteria because they have thicker membranes. Iodine fixes the dye and the slide is washed with alcohol. Then it will be counter stained with congo red which stains the gram negative bacteria.
Acid fast technique
A lipid solvent will carry the dye into the bacteria and stain them, the slide is then washed with acid. A counterstain is then used on the bacteria that did not absorb dye.
Magnification
Amount of times larger the image of the object is compared to the actual size of it.
Resolution
Ability to distinguish two individual objects as separate entities
Transmission Electron Microscope (TEM)
Beam of electrons focused through the specimen like a light microscope. Resolution is 0.5nm
Scanning Electron Microscope (SEM)
Beam of electrons sent across the specimen and then collected to produce a 3D image. Resolution is 3-10nm
Artefacts
Visible structures that are created by the preparation of the specimen e.g. bubbles and can mess with the experiment
Fluorescence
When light is absorbed and then re emitted
Laser Confocal Microscope
A laser which is a single beam of light is emitted from the illumination pinhole, it goes through the dichroic mirror and then hits the focal plane which is where the sample is. If it hits the focal plane, it will be reflected in the same path it hit the focal plane, go through the dichroic mirror again and focus into the confocal pinhole to produce an image. If it doesn’t hit the focal plane it will blur and image would have less resolution.
