Studied by 0 people
Cell Size
Most cells are between 1 and 100 um in diameter, too small to be seen by the unaided eye.
Light Microscopes
Visible light is passed through a specimen and through glass lenses. Lenses refract (bend) the light, resulting in the image being magnified.
Magnification
The ratio of the object's size to its real size.
Resolution
The measure of clarity of the image or the minimum distance between two points.
Contrast
Visible differences in parts of the sample.
Effective Magnification of Light Microscopes
Light microscopes can magnify effectively 1000 times the size of the specimen.
Techniques to Enhance Contrast
Various techniques enhance contrast and enable cell components to be stained or labeled.
Limitations of Light Microscopy
Most subcellular structures, including organelles, are too small to be resolved by light microscopy.
Scanning Electron Microscopes (SEMs)
SEMs focus a beam of electrons onto the surface of a specimen, providing images that look 3D.
Transmission Electron Microscopes (TEMs)
TEMs focus a beam of electrons through a specimen and are mainly used to study the internal structure of cells.
Cell Fractionation
Breaks up cells and separates the components using centrifugation.
Organelle Function Determination
Fractionation enables scientists to determine the functions of organelles.
Correlating Cell Function with Structure
Biochemistry and cytology help correlate cell function with structure.
Note 
Flashcard (22)