BIOL240 Final: Biol 140L Final Exam Review
Document Summary
Though all organisms are the same colour, a simple stain allows one to distinguish the morphologies of cells such as cocci, rods, spirals and vibrios. Most common dyes are methylene blue, basic fuchsin and crystal violet positive staining procedure stain is basic and has a positive chromophore that is attracted to the negative charge on the outer surface of organisms. Used loeffler"s methylene blue stain for 1-2 minutes on escherichia coli, bacillus subtilis and staphylococcus epidermidis and rinse with water. The light microscope consists of a lens system, a controllable light source and a geared mechanism to adjust the distance. The objective is nearest the specimen and magnifies the specimen and the ocular (eyepiece lens) is at the top of the microscope. Condensor contains lenses that collect and concentrate light. The amount of light can be adjusted by opening and closing the iris diaphragm.