front 1 Which of the following pairs is correctly matched? | back 1 Atomic force microscopes & DNA |
front 2 What does refraction mean? | back 2 A measure of the light-bending ability of medium |
front 3 Place these structures of the compuound light microscope in the order that light passes through them on the way to the observer's eyes:
| back 3 Illuminator -->condenser-->specimen-->objective lens (ocular lens). |
front 4 What is the correct order for the Gram stain process? | back 4 crystal violet--> iodine--> decolorizer--> safranin |
front 5 The acid-fast stain differs from the Gram stain procedure in the decolorizing agen used. What is the reagent used in an acid-fast stain, and why is it necessary? | back 5 Acid-alcohol is used to remove the primary stain from bacteria that do not have waxy cell walls. |
front 6 A student completes a Gram stain on a bacterial smear that has a mix of gram-negative and gram positive organisms but forget to apply the safranin counterstain. What would be the outcome of the Gram stain? | back 6 The gram-positive organisms would appear purple, and the gram-negative organisms would be colorless. |
front 7 Which of the following is NOT visible through a compund light microscope? | back 7 0.02-micrometer ribosome |
front 8 In the Gram stain, what is the purpose of the counterstain? | back 8 To make gram-negative cells visible |
front 9 Which of the following statements about electron microscopy & light microscopy is FALSE? | back 9 Both the electron micorscope and the light microscope use the same wavelengths for illumination. |
front 10 In the Gram stain, what is the purpose of the decolorizer? | back 10 To selectively remove stain from cells |
front 11 Before cells are stained, the specimen must be fixed. Fixing a specimen accomplishes all of the following EXCEPT which one? | back 11 Fixation differentiates the various cells being observed. |
front 12 Which of the following staining procedures is matched with the principal use for that particular stain? | back 12 Endospore stain to distinguish dormant structures formed during adverse environmental conditions |
front 13 What metric unit would be most appropriate for expressing the size of most viruses? | back 13 Nanometer |
front 14 A student is observing a Gram stain on the 100x (oil immersion) lens. The image appears cloudy & dark. Which of the following actions will NOT increase the clarity of the image? | back 14 Lower the stage to increase the distance between the object & the objective lens. |
front 15 Immersion oil is used with the 100x objective lens of the compound light microscope to ______. | back 15 prevent the loss of resolution due to refraction |
front 16 Consider the following situations, and determine when a simple stain should be used instead of a Gram stain. | back 16 A microbiologist is trying to determine whether an organism has flagella. |
front 17 If you use a compound light microscope, a 2-micrometer bacterial cell is best seen at which magnification? | back 17 1000x |
front 18 Which of the following types of microscopy allows organisms to be identified based on antigens, even if the organisms are inside a cell? | back 18 Fluorescent microscopy |
front 19 A student is observing an object that displays the internal detail on virus at great magnification. Which type of microscope is used for this image? | back 19 Transmission electron microscope |
front 20 A microscopist is studying the surface pores on a bacterial specimen. Which microscope provides the best three-dimensional surface structure image? | back 20 Scanning electron microscope |
front 21 Which of the following is the most convenient & appropriate unit for expressing the size of an average bacterial cell? | back 21 Micrometer
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