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Lecture 1--microscopy

Cell size units of measurement 1m 10 6 m 1nm 10 9 m 1

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Unformatted text preview: down to 200microns (know that there are 2 onjects as opposed to 1) light microscope: down to 200 nano meters Size and scale http://learn.genetics.utah.edu/ content/begin/cells/scale/ Microscopy: the key tool of cell biologists • • Robert Hooke discovered cells in the 1660s During the observation of thin slices of cork, Hooke saw honeycomb-like structures called “cells” Flea--from Hooke’s micrographia Cell Size Units of Measurement 1µm = 10-6 m 1nm = 10-9 m 1Å = 10-10 m Conventional microscopy Specimens for light microscopy 1. Can be performed with whole tissues or slices; thicker specimens allow less light to pass 2. Often mounted on a slide with a coverslip 3. Can be stained with histological dyes to enhance contrast condenser: lens that focuses light on sample lense: objective Three types of light microscopy Bright Field Phase Contrast Interference (Nomarski) Immortalized cells can be passaged indefinitely -- Isolated from tumors (activated oncogenes or inactivated tumor suppressor genes) -- Divide indefinitely in culture HeLa cells have been maintained since 1951 Tissues can be sliced into sections Tissues can be sliced into sections example of parafin block, embryo suspended in there PFA 1. Fix put it in a chemical thatcross links everything in the cell; vcreates a s tatue of that cell 2. Embed in agar, paraffin or plastic 4. Slice with a very sharp blade on a microtome or vibratome 3. Trim the block vibrotome, microtome; trim to be able to fit in the slide 5. Place slices on a slide, stain (if desired) and image brightfield; fiberblast cell s itting on cover s lipt; can see c ells and nucleus a common tissue stain: hematoxylin and eosin (H&E) another hisological stain: Golgi staining stain; sticks onl y to some parts of c ells creating c ontrast only some of the c ells take up the dye stsining good to tell gyou that there is a c ell here. Neuro-eStore website Fluorescence Microscopy allows specific cellular structures to be highlighted with fluorescence Biochemical Soul blog nuclei blue, red = cytoskeleton Fluorescence Microscopy need tissue to have a fluorescent moecule. Fluorophores - molecules that absorb invisible, ultraviolet radiation (excitation) and emit a portion of that energy in longer wavelengths. mercury light or LED Cells can be labeled with fluorophores that appear brightly color...
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