BIOL240 Study Guide - Final Guide: Gram Staining, Methylene Blue, Acid Dye
22 Aug 2016
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Document Summary
A single stain is used and all cells and structures generally stain the same colour, regardless of type. Allows one to distinguish bacterial cells of various morphological types. Positive staining procedure: a positively charged and basic stain that is attracted to the slightly negative bacteria. Commonly used dyes: methylene blue (blue), basic fuchsin (red), crystal violet (purple) The magnification achieved by a compound microscope is the result of two systems of lenses; the objective(4x, 10x, 40x, 100x) and the ocular (10x) Oil immersion objective: one small drop of immersion oil is smeared onto the slide for. Total magnification of the image: objective x ocular. Magnification of specimen in drawing: size of specimen in drawing ( m) divided by estimated or actual size of image ( m) Bacillus subtilis: rods, in lines or clusters. Escherichia coli: rods, singly or in clusters. Rhodospirillum rubrum: spiral, singly or in clusters.
