PORTAGE LEARNING: MICROBIOLOGY, MODULE 3 QUESTIONS AND ANSWERS (100% PASS)

micrometer - Answer one millionth of a meter nanometer - Answer one billionth of a meter two critical factors that influence our ability to see an object - Answer resolution and contrast resolution - Answer the distance between two objects at which the objects still can be seen as separate contrast - Answer the difference in light absorbance between two (objects) the closer two objects are to each other the __________________ the resolution requirement - Answer greater the ________________ the contrast between an object and its background, the harder it will be to see the object - Answer lower bright field microscope - Answer simplest form of light, or optical, microscopy/light, most often emitted from a standard halogen bulb, enters the microscope from the base (bottom) and is reflected via mirrors towards the sample before the light reaches the sample, it first passes through a ________________ converging the light beams into a focused area on the sample - Answer condenser iris diaphragm - Answer controls the amount of light that passes through the sample and into the objective lens objective lens - Answer the lens closest to the sample and yields the greatest amount of magnification the degree of magnification is ______________________ to the amount of light needed/to image samples clearly at higher magnifications, more light is required - Answer directly proportional ocular lens - Answer eyepiece 10x - Answer most common power of ocular lens total magnification - Answer objective x ocular lens= staining - Answer 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. phase contrast microscope - Answer able to visualize certain structures that would otherwise be invisible/ can provide detailed images of live cells without staining./uses specialized condensers and objectives, it amplifies the slight differences between cells and the surrounding medium (background) to make the cells highly distinguishable/can be used to visualize cell movements dark field microscope - Answer can be used to greatly increase the contrast between a specimen and background, resulting in a dark background with bright objects in it/reflects light off of the specimen at an angle/does not permit the visualization of intracellular structures fluorescence microscope - Answer takes advantage of fluorescent molecules called fluorophores to visualize cells on a dark background/ energy of the incoming light is in the form of the ultraviolet (UV) spectrum. UV light - Answer _____________ excites different fluorophores at varying wavelengths, enabling scientists to use a wide array of colors during imaging GFP, YFP and RFP - Answer can be expressed in a cell, nonspecifically illuminating the cell as a whole; linked (coupled) to a normal cellular protein of interest whereby the fluorescent color is indicative of protein movement and localization; or used as tags on molecules or antibodies used to designate the presence (fluorescence detected) or absence (no fluorescence) of a specific protein target confocal (laser scanning) microscope - Answer combines the usefulness of fluorescence microscopy with the ability to visualize cells in in 2D or 3D/use lasers to focus on a single plane within an object and with a higher degree of accuracy electron microscope - Answer used to visualize incredibly small specimens/ use beams of electrons (rather than light), which have significantly shorter wavelengths than light to increases its resolution capacity to less than 1nm transmission electron microcope (TEM) - Answer uses thin slices of a sample, heavily treated and coated in preservatives, placed between the electron beam source and the detector scanning electron microscope - Answer 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