A2.2 Cell Theory and Microscopy Flashcards
Viruses
-non cellular because of behaviour, organelles, and are considered dead outside of a host cell
Cell theory
-living organisms are composed of cells
-the cell is the smallest unit of life
-all cells come from pre-existing cells
Light microscope
-uses glass lenses to bend light to magnify images
-magnification is determined by lenses used
-1µm=1x10^-6 metres or 1000µm=1mm
Magnification
-the number of times larger an object or specimen is
Fraction
-reduced in size
Immunofluorescent stain
-use antibodies that are linked to fluorescent probes to specifically target a cellular component of choice
Fluorescent stain
-synthetic dyes can be used to bind cellular components to resolve specific structures
-ethidium bromide or DAP
Transmission electron microscope (TEM)
-electrons beam through the specimen on photo film
-3D
-great detail
-small field of view
Scanning electron microscope (SEM)
-provides surface detail
-3D
-lower magnification
-usually coats the specimen in a dense metal (gold)
Cryogenic electron microscopy
-freezing samples prior to reviewing to generate images of a comparable to X-ray crystallography
-allows for the determination of molecular structures at near atomic resolution
Freeze fracture
-frozen specimen is cracked along a plane to study the internal cellular structures
Advantages to light microscopes
-visible movement in living specimens
-cheaper
-portable
-preparation is simple
-larger field of view with actual colour
Advantages to electron microscopes
-better resolution
-increased magnification
-sees details unavailable on a light microscope
Microscope magnification formula
-magnification=drawing size/actual size
-REMEMBER TO CONVERT UNITS
