Portage Learning: Microbiology, Module 3 |53 Questions| With Correct Answers.

gram-negative bacteria {Ans: have a relatively thin peptidoglycan layer followed by an outer membrane composed of lipopolysaccharides (LPS)}scanning electron microscope {Ans: uses a beam of electrons but the image is obtained as the electrons reflect off (not through) the surface of the specimen/samples are coated with either gold or palladium to enhance electron reflection/can only be used to generate a detailed three-dimensional 'shell' model of the surface of a specimen}stains {Ans: can be used to examine tissues (muscle or connective), specific types of cells (blood, bacterial, etc) or even organelles within an individual cell (nucleus, ER, etc)}simple staining {Ans: uses a solution of a positively charged dye such as methylene blue, crystal violet, safranin or fuschin to bind to and stain the negatively charged membrane of the microorganism}staining {Ans: required due to the limitation of resolution on unstained cells, (i.e.) often the flat and transparent regions of a cell may appear invisible under bright field conditions/with various dyes, these regions can become labeled and thus visualized.}objective lens {Ans: the lens closest to the sample and yields the greatest amount of magnification}