BIOD 171 PORTAGE LEARNING EXAM QUESTIONS AND 100% CORRECT ANSWERS|LATEST 2025/2026

BIOD 171 PORTAGE LEARNING EXAM
QUESTIONS AND 100% CORRECT
ANSWERS|LATEST 2025/2026
Define the measurements micrometer and nanometer. - ANSWER-
B B B B B B B



A micrometer is one-millionth of a meter and a nanometer is one-billionth of a meter.
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What are the two critical factors that influence your ability to see an object? - ANSWER-
B B B B B B B B B B B B B B B



The resolution and the contrast. Resolution is the distance between two objects where
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you can still see them as separate. Contrast is the difference in light between two objects.
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If you wish to increase the amount of light going into a microscope, what part would you adjus
B B B B B B B B B B B B B B B B B



t? - ANSWER-
B B The iris diaphragm.
B B




As light passes through a microscope, what is the last piece that light passes before reaching y
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our eyes? - ANSWER-
B B B



Once light passes through the sample and the objective lens, it passes through the OCU
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LAR LENS. B




How is the total magnification of an object calculated? - ANSWER-
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It is calculated by multiplying the power of the objective and the power of the eyepiece
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.



What is one limitation of fixing your sample? - ANSWER-
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Fixing your sample requires you to irreversibly kill your sample.
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This can make it impossible to determine the cell movement. You could distort the shape and s
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tructure.



Phase-contrast microscopy provides what benefits to imaging? - ANSWER-
B B B B B B B B Phase-
contrast microscopy provides detailed images without staining.
B B B B B B




What is the distinguishing feature of dark field microscopy? - ANSWER-
B B B B B B B B B B



Dark field microscopy reflects light off of the specimen at an angle..
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, Unlike brightfieqld microscope, fluorescence microscopes illuminate samples through what s
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pectrum? - ANSWER- B B The Ultraviolet Spectrum.
B B




What is the primary difference between TEM and SEM? - ANSWER-
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The electron passes through the sample during TEM where as the electron is reflected
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off the sample during SEM.
B B B B




Gram staining is based on what basic principle? - ANSWER-
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With the basic observation that different types of bacteria react differently to various d
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yes.



What is a key determinant in bacteria being Gram-positive? - ANSWER-
B B B B Gram- B B B B B B



positive have a thick peptidoglycan layer. Uses crystal violet and iodine. The resulting mixture i
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s a purple coloration of the cell.
B B B B B B




What is the purpose of heat fixing a sample? - ANSWER-
B B B B B B B B B B



Heat fixing makes sure the samples are tightly adhere to the glass slide.
B B B B B B B B B B B B




What is the primary purpose of a wet mount? - ANSWER-
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Wet mounts are often perform to visualize live cells and to see the motility and behavio
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r of an organism.
B B B




The acid-fast stain is most often used to identify what specific microorganism? - ANSWER-
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Mycobacterium tuberculosis is the most common for an acid-fast stain. B B B B B B B B B




What is the total magnification of a sample imaged with a 60x objective and a 10x eyepiece? -
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B ANSWER- 60 x 100 = 600x magnification
B B B B B




True or False: A cell that is adherent, flat, and unstained is easily identified using bright field mi
B B B B B B B B B B B B B B B B B



croscopy. - ANSWER- B B False