LIFESCI 4 Chapter Notes - Chapter 6.1 - 6.3: Chromatin, Nuclear Lamina, Protein Structure
Document Summary
6. 1: to study cells, biologists use microscopes and the tools of biochemistry. Light microscopes first used by renaissance scientists: visible light passed through specimen, lenses bend the light to project image into eye. Electron microscopes focus a beam of electrons through the specimen: 2 types of electron microscopes, scanning electron microscope: useful for detailed study of the surface of a specimen. Electron beam scans surface, usually coated with thin film of gold. The beam excites electrons on the surface, which are detected by a device: transmission electron microscopy: used mainly to study the internal ultrastructure of cells. Aims electron beam through thin section of specimen. Electron microscopes reveal organelles that are impossible to resolve with the light microscope. 6. 2: eukaryotic cells have internal membranes that compartmentalize their functions. Prokaryotic and eukaryotic cells both cells have a cytoplasm: region between membrane and nucleus. Prokaryotic cells concentrate the dna in the nucleoid; there is no membrane.
