BIO152H5 Lecture Notes - Lecture 4: Scanning Electron Microscope, Cell Membrane, Optical Instrument
Document Summary
6. 1 biologists use microscopes and the tools of biochemistry to study cells. Light microscopes (lm): optical instrument with lenses that refract (bend) visible light to magnify images of specimens. Magnification: ratio of object"s image size to its real size. Resolution: a measure of clarity of the image. Contrast: difference in brightness between light and dark areas of an image. Lm cannot see something smaller than 200 nm and em usually cannot resolve anything smaller than 2 nm. Scanning electron microscope (sem): used to study the fine details of cell surfaces appears three- dimensional. Transmission electron microscope (tem): used to study the internal structure of thin sections of cells. Takes cells apart and separates major organelles from other subcellular structures. 6. 2 eukaryotic cells have internal membranes that compartmentalize their functions. Domain eukarya is eukaryotic and includes the kingdoms protists, fungi, animals and plants.
