Download Microbiology Lab Midterm (Lab Notebook Questions) and answers rated A+ 2025 and more Exams Microbiology in PDF only on Docsity!
Microbiology Lab Midterm (Lab
Notebook Questions) and answers rated
A+ 2025
What is located in the headpiece that bends light rays toward the ocular lenses? - correct answers prism Name the only type of paper and three fluids that may be used to clean objective and ocular lenses? - correct answers -lens paper -acetone -xylene -ethyl alcohol What is the most important aspect in caring for the microscope? - correct answers keeping it clean and using it properly Which way does the stage move when you rotate the coarse adjustment knob towards you? - correct answers down Make a statement concerning the distance the stage moves up or down when using the coarse adjustment compound to the fine adjustment. - correct answers Fine adjustment: sharpens image Coarse adjustment: moves the stage and provides the most focus by changing distance between lens and specimen Your microscope is equipped with a series of 3 lenses and is therefore called a _______ microscope. - correct answers compound
An image is produced when light is absorbed by a dark opaque object. The background has a bright white background. Your microscope is therefore also called a ________ microscope. - correct answers bright field The lenses nearest your eyes are the eyepieces or ______ lenses. - correct answers ocular What is the magnifying power of there lenses? - correct answers 10x What is the collective name for the four lenses located nearest to the object being viewed? - correct answers objective lenses What is the name and magnification of the red banded lens? - correct answers 4x scanning lens What is the name and magnification of the yellow banded lens? - correct answers 10x low power lens What is the name and magnification of the blue banded lens? - correct answers 40x high power lens What is the name and magnification of the white banded lens? - correct answers 100X oil immersion lens
Define refractive index? - correct answers the number of degrees light rays are bent when passing through an object Immersion oil must have the same refractive index as ______ to be if any value. - correct answers glass Why do you think immersion oil is used between the slide and the 100x objective lens? - correct answers to get more detail What might happen if the slide is not securely placed, or the slide clip is released too fast? - correct answers it could fall out and break The ________ mechanical stage knob moves the stage front to back. - correct answers large The ____ mechanical stage knob moves the slide holder left to right. - correct answers small Parfocal means the image remains in focus after you have rotated the _____________________ from 4x to 10x. - correct answers revolving nosepiece As you increase magnification from 4x to 10x to 40x, what happens to the intensity of light that reaches your eyes? - correct answers it gets darker, you have to make the light stronger What part of the microscope should you use to increase the amount of light traveling through the specimen and reaching you eye? - correct answers iris diaphragm lever
Which objective lens requires oil immersion? - correct answers 100x Which objective lens has the greatest working distance? - correct answers 10x Which objective lens requires setting the iris diaphragm lever almost all the way open (to the left)? - correct answers 40x How does depth of field change as you increase magnification? - correct answers it increases How does depth of field change as you decrease magnification? - correct answers it decreases Concepts of depth of field and working distance are important to realize when using the oil immersion (100x) objective lens which provides what total magnification? - correct answers 1000x What is the total magnification when using the scanning lens? - correct answers 40x What is one special advantage of using the TEM? - correct answers it is capable of enlarging an image 1,000,000x The TEM is used most often to look at what group of microbes? - correct answers viruses What are 3 advantages of using SEM over TEM? - correct answers -live specimens can be used
What is the term for a high white blood cell count? - correct answers Leukocytosis What is the term for low white blood cell count? - correct answers leukopenia Define "in vitro"? - correct answers on glass or in the lab Define "in vivo"? - correct answers in the body What is plasma? - correct answers liquid portion of the blood when in blood stream What is serum? - correct answers liquid portion of the blood in a tube after ventipuncture without clotting factors What is the medical term fro drawing blood from a patient? - correct answers ventipuncture What is the medical term for blood clotting? - correct answers hemostasis What are the 2 principal ways of preparing a microbial specimen for observation with a light microscope? - correct answers stains and wet mount What is the definition of an artifact as it relates to microscopy? - correct answers a. simple object, tool, or ornament showing human workmanship b. a product, as a structure on a prepared microscope slide, of artificial character due to extraneous human agency
It is essential to differentiate between true motility and _______ ________, a vibratory movement of cells due to bombardment by water molecules. - correct answers brownian motion What are two reasons for disinfecting your table and washing your hands before and after each experiment? - correct answers -don't contaminate yourself and others -washing hands before and after Crystal violet, safranin, and methylene blue are examples of _________ charged chromogens that bind the ________ charges found in bacteria - correct answers a. positivity b. negativity What is the most common error in making a smear from a nutrient agar slant?
- correct answers accidentally taking agar with the bacteria Why should you never leave your loop or needle in the bact-incinerator? - correct answers it will melt! What are the advantages of differential staining procedures over simple staining techniques? - correct answers can help identify a culture with one or more types of bacteria/microorganism What is the function of each step of the Gram stain? - correct answers to see if the organisms cell wall is gram + or gram - Primary stain (crystal violet) - correct answers first binds to the negative charges of both gram + and gram - cells (mostly RNA)
What would happen if you did not heat fix Bacillus subtilis to the slide prior to the primary stain? - correct answers it would be removed What is the decolorizer in the endospore stain? - correct answers water What part of Bacillus subtilis is decolorized? - correct answers vegetable cells only Define sporogenesis and germination? - correct answers -sporogenesis: a mechanism that ensures cell survival under extreme environmental conditions -germination: the free spore reverts back to a metabolically active resistant VC Compare the appearance of Bacillus subtilis following simple staining with methylene blue and after the endospore stain? - correct answers red endospores-green VC simple- VC blue ES colorless What if you used acid alcohol as the decolorizer instead of water? - correct answers it would not hurt spores, you would have the same results What if you used safranin as the primary stain and malachite green as the counterstain - correct answers VC - green endospore - red You did not apply steam heat with the primary stain... - correct answers it would not stain malachite green What is the genus of aerobic spore formers? - correct answers Bacillus
What is the genus of anaerobic spore formers? - correct answers Clostridium What are the endospores composed of that makes them so difficult to stain? - correct answers Diplicolinic acid List 4 environmental factors that endospores resist? - correct answers - excessive heat -freezing -radiation -desiccation List 4 medically significant spore forming bacteria? - correct answers - Bacillus anthracis (anthrax)
- Clostridium botulinum (botulism)
- Clostridium perfringens (gangrene)
- Clostridium tetani (tetanus) How does the capsule protect bacteria from host immunity? - correct answers it surrounds the bacteria adhering to the cell wall and is a very important mechanism of bacterial pathogensis because the capsule provides microbial resistance to the host Why does capsule formation depend on environmental factors and nutritional status? - correct answers A capsule is normally formed when a host immunity is low and there are plenty of nutrients available from a primary viral infection
Because of this property mycobacteria are called acid fast while microbes easily decolorize by acid alcohol are non-acid fast What is found in the cell wall of acid fast bacteria that resists decolorization with acid alcohol? - correct answers mycolic acid Name the arrangement morphology of Mycobacterium tuberculosis? - correct answers filamentous
