MCB 3020C Lecture Notes - Lecture 2: Antonie Van Leeuwenhoek, Scanning Electron Microscope, Fluorescence Microscope
Document Summary
Antoni van leeuwenhoek: first to describe bacteria. 1. 5 light microscopy and the discovery of microorganisms. Magnification: the ability to make an object larger. Resolution: the ability to distinguish two adjacent objects as distinct and separate: limit of resolution for light microscope is about 0. 2 um. Staining improves contrast: dyes are organic compounds that bind to specific cellular materials, basic dyes: positively charged, bind strongly to negatively-charged cell components, examples: methylene blue, crystal violet, and safranin, simple stain uses dried cells. Differential stains: different kidns of cells are different colors: example: gram stain differences because of cell wall structure, bacteria can be divide into two major groups, gram-positive bacteria appear purple-violet, gram-negative bacteria appear pink. Aspectic technique: collection of practices that allow preparation and maintenance of sterile chemicals. Pure cultures: cells from only a single type of microorganism. Enrichment culture techniques: isolate microbes having particular metabolic characteristics from nature. Scientists used these techniques to answer two questions: 1.
