Chapter_7_Outline - Ch 7: A Tour of the Cell I. How We...

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Ch 7: A Tour of the Cell I. How We Study Cells A. Magnification is the ratio of an object’s image to its real size; resolving power is the minimum distance two points can be separated and still be distinguished as two separate points. B. In light microscopes visible light is passed through the specimen and then through glass lenses; the resolving power of the light microscopes are limited, yet these microscopes can magnify up to 1000 times the size of the specimen. Transmission electron microscopes use electron beams through thin sections of the specimen, allowing study of the internal ultrastructure of cells. Scanning electron microscopes use electron beams to the surface of a sample, allowing study of the surface of a specimen. The biggest disadvantage of electron microscopes is that they kill the cells. C. Fractionization begins with homogenization and then spins the substance at low speeds to divide it into pellets and supernatants. Then the supernatant is centrifuged at a higher speed to collect smaller components. This technique allows researchers to prepare specific components of cells in bulk quantity in order to study their composition and functions. I. A Panoramic View of the Cell D. The major difference between prokaryotic and eukaryotic cells is that chromosomes of eukaryotic cells are located in a membrane-enclosed organelle (nucleus), unlike prokaryotic cells. E. Lower limits to cell size exist because of logistics of carrying out metabolism, while upper limits to cell size exist because of the ratio of the volume to the surface area of a cell. F. Compartmentalization in eukaryotic cells creates different local environments in the various compartments, allowing incompatible processes to go on simultaneously inside the same cell. II.
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This note was uploaded on 06/15/2010 for the course FDST 4080 taught by Professor Pegg during the Spring '10 term at University of Georgia Athens.

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Chapter_7_Outline - Ch 7: A Tour of the Cell I. How We...

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