BIOL 1107 Chapter Notes - Chapter 6: Scanning Electron Microscope, Electron Microscope, Cell Fractionation
Document Summary
Nerve cell muscle cell moving in eyes. The cell is the fundamental unit of life. 1665 robert hooke first saw cell walls. Light microscope (lm): visible light passed through specimen through glass lenses. Magnification: ratio object image size to real size. Electron microscope (em): focuses a beam of electrons onto surface or through cell. Scanning electron microscope (sem): used for detailed study of topography of a specimen. Transmissions electron microscope (tem): studies internal structure of cells. Both good for cell function and structure. Cell fractionation: takes cells apart and separates major organelles and other subcellular structures from one another. In eukaryotic cell dna is in nucleus. In prokaryotic cell dna is in nucleoid (not membrane-enclosed) Cytoplasm: interior of either type of cell. Prokaryotic cell 1-5 um smaller found in bacteria and archaea. Eukaryotic cell 10-100 um larger found in plants, protists, fungi, animals. Plasma membrane: selective barrier; allows oxygen, nutrients and wastes for entire cell.
