Microbiology Lab Practical Questions with Complete Solutions

Microbiology Lab Practical Questions with Complete Solutions The microscope used in the laboratory is what type of microscope? Compound Binocular Light The ability of a microscope to reveal fine detail is known as? resolution The 10X eyepiece used in combination with a 45X objective produces a magnification of? 450X Another name for the 100X objective lens? oil immersion when putting the microscope away, which objective should be in place? low power What part of the microscope regulates the amount of light entering? condenser what part of the microscope is used if some focusing adjustment is needed with high power? fine adjustment Identify the person who was first to observe microorganisms Anton Van Leeuwenhoek Which of the following cannot be seen with your laboratory microscope? Bacteria, Fungi or Viruses? Viruses The primary stain used in the endospore procedure is? malachite green What color do the endospores stain? green why do you steam the endospore stain? helps stain penetrate endospore wall Another name for the endospore stain is? Schaeffer Fulton Method What counterstain is used in an endospore stain? Safarin Name 2 genera most noted for the production of endospores? Bacillus and Clostridium An endospore is what type of cell? vegetative or dormant? dormant The color produced which indicates an organism uses citrate as a carbon source blue - positive E. coli is citrate positive or negative? negative Why is it necessary to heat fix bacterial cells? enforces bacteria to stick to slide A common stain used in simple staining is? crystal violet Give 2 reasons for cooling the slide before applying the stain to prevent cracking and precipitate The stain used in a negative stain is? nigrosin why is it called a negative stain? makes light structures dark and dark structures light The easiest staining procedure is? simple stains why is the stain valuable? objects visible under microscope The type of mount that you use in the lab to study organisms for a short period of time is? temporary mount why should you flame the inoculation loop while using? kills bacteria A culture in which you have many different types are associated together is considered to be? mixed culture The single most important bacteriological stain is? Gram stain The counterstain used in Gram stain is? safarin What is the decolorizing agent in Gram staining? 95% Ethyl Alcohol Gram negative bacteria stain what color? Red Gram positive bacteria stain what color? Purple The most critical part of Gram staining is? decolorization What technique is used to maintain sterility and avoid contamination is called? Aseptic technique Turbidity can best be seen where? agar plate, broth tube or agar slant? broth culture what is the purpose of flaming your loop avoid contamination The primary stain in an acid fast stain is? carbolfuschsin stain The counterstain in an acid fast stain is? methylene blue or brilliant green An example of an acid fast positive organism is? Mycobacterium sp. Acid fast positive organisms stain what color? Red Acid fast negative organisms stain what color? Blue The decolorize used in acid fast staining is? 95% Acid alcohol what enables the acid fast bacteria to retain the primary stain? heat When identifying organisms according to growth pattern - what precaution should be taken after inoculating the tubes? do not shake the tube