Lecture 2 Flashcards
Light Microscope
Earliest tool for cytologists, allowed identification of organelles within cells
Organelles
Membrane-bound structures
Compound Microscope
Microscopes with 2 lenses, increased magnification and resolution
Microtome
The ‘deli-slicer’ of cell biology, allowed for the preparation of very thin slices of samples
Staining
A function of the chemical properties of the substances that make up the structure, used to improve the contrast between structures similar in size and shape
Hematoxylin
Positively charged/basic blue stain, binds to negatively charges/acidic structures (e.g. DNA)
Eosin
Negatively charged/acidic orange-red stain, binds to positively charged/basic structures
Tissue Microarrays
TMAs, chips/slides with tiny slices of many different samples (e.g. tumours)
Limit of Resolution
How far appart objects must be to appear as separate objects
Numerical Aperture
Refractive index of the material the light is passing through multiplied by the sine of the angle
Phase Contrast Microscope
Exploits differences in the phase of light passing through a structure with a refractive index different than the surrounding medium
Differential Interference Contrast Microscope
Exploits differences in the phase of light passing through a structure with a refractive index different than the surrounding medium
Fluorescence Microscopy
Detects fluorescent dyes or labels to show locations of substances in the cell
Confocal Scanning
Uses a laser beam to illuminate a single plane of fluorescently labeled specimen
Fluorescence
Refers to the absorption of light by a molecule at a certain wavelength followed by the emission of light with a longer wavelength
DAPI
A nucleophilic, DNA binding dye which appears blue
Phalloidin
Green stain that binds to actin (microtubules)
Super-resolution Microscopy
Use stochastic activation of fluoroscopes to differentiate between objects
Atomic Force Microscopy
Image is built up by successive scans
Electron Microscopy
Uses a beam of electrons rather than light to improve resolution and magnification
Transmission Electron Microscopy
Electrons are transmitted through the specimen
Scanning Electron Microscopy
The surface of a specimen is scanned by detecting electrons deflected from the outer surface
