The basic unit of biology; every organism consists of cells or is a single cell.
Study of cellular structure and organization
Study of chemical reactions of biomolecules
study of interactions and regulations between cellular systems involving DNA, RNA, and protein synthesis.
The Light Microscope
Cell biologist most important tool Resolution is ~0.2 um; allows for live cell imaging.
Developed the crude light microscope Coined the word "cell"
Antonie van Leeuwenhoek
observed living cells with a better microscope
the ability to discriminate two closely placed structures
a measure of the increase in the diameter of a structure
In a stained section of tissue will absorb light and generate contrast in the sample
Proportional to the density of the matter (refractive index); light waves slow down when passing through the sample
A focused laser beam provides force, depending on refractive index, to physically hold and move microscopic objects.
Detection of specific molecules (proteins, ions, organelles) by coupling (directly or indirectly) to a fluorochrome that will emit light when excited. For use with living or fixed tissues
How do we use epifluorescence microscopy with non living cells?
Indirect Immuno-fluorescence (2 antibodies) a) cells are fixed maintaining integrity of proteins b) Primary antibody exposure which binds to antigen c) Secondary antibody exposure which binds to primary antibody. Has fluorochrome
Confocal epifluorescence light microscopy
microscope uses a special dichroic (dichromatic) mirror mirror reflects light shorter than a certain wavelength, and passes light longer than that wavelength Adding a pinhole removes background haze
How do we use epifluorescence microscopy with living cells?
Green fluorescent protein (GFP) and dyes allow us to see living cells
Transmission Electron Microscope (TEM)
a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it passes through. An image is formed from the interaction of the electrons transmitted through the specimen; the image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, or to be detected by a sensor such as a CCD camera. Images of the inside of a cell
Who are Knoll and Ruska?
developed the Electron Microscope in the 1930's
How do we fix a sample for TEM?
a) Fix cells with aldehydes or rapid freezing and stain with metals b) Dehydrate c) Embedded in epoxy-based resin d) Cut sample with a ultramicrotome (70nm)
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