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BIOD 151 Portage Learning Microbiology Module 3 (2025) Exam With Actual Questions And Answ, Exams of Nutrition

A nanometer is defined as: ✔✔10-9 A nanometer is defined as one-billionth of a meter True or False: A nanometeris longer than a micrometer ✔✔False. A nanometer is 1,000 times smaller than a micrometer. Resolution and contrast are two critical factors that influence your ability to see an object. Explain each. ✔✔Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one.

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A nanometer is defined as: ✔✔10-9
A nanometer is defined as one-billionth of a meter
True or False: A nanometeris longer than a micrometer ✔✔False. A nanometer is 1,000 times
smaller than a micrometer.
Resolution and contrast are two critical factors that influence your ability to see an object.
Explain each. ✔✔Resolution refers to the distance between two objects at which the objects still
can be seen as separate. Poor or low resolution means two (or more) objects may appear as one.
*Contrast is the difference in light absorbance between two objects. Poor contrast gives a high
background and makes the visualization of multiple objects difficult. For instance, trying to
identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the
middle of a sunny afternoon (bright light against 2 dark objects = high contrast).
Assuming a constant (non-adjustable) light source power, identify the part of the microscope you
would adjust to limit the amount of light entering the microscope. ✔✔The iris controls the
amount of light that passes through the sample and into the objective lens. Thus, it can be
adjusted (opened or closed) to alter the amount of light.
BIOD 151 Portage Learning
Microbiology Module 3 (2025) Exam
With Actual Questions And Answers
100% Solved Graded A+
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A nanometer is defined as: ✔✔ 10 - 9 A nanometer is defined as one-billionth of a meter True or False: A nanometeris longer than a micrometer ✔✔False. A nanometer is 1,000 times smaller than a micrometer. Resolution and contrast are two critical factors that influence your ability to see an object. Explain each. ✔✔Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one. *Contrast is the difference in light absorbance between two objects. Poor contrast gives a high background and makes the visualization of multiple objects difficult. For instance, trying to identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against 2 dark objects = high contrast). Assuming a constant (non-adjustable) light source power, identify the part of the microscope you would adjust to limit the amount of light entering the microscope. ✔✔The iris controls the amount of light that passes through the sample and into the objective lens. Thus, it can be adjusted (opened or closed) to alter the amount of light.

BIOD 151 Portage Learning

Microbiology Module 3 (2025) Exam

With Actual Questions And Answers

100% Solved Graded A+

What is the total magnification (relative to your eye) of a sample imaged with a 60x objective and a 10x eyepiece? Show your math ✔✔60 x 10 = 600x magnification True or False: Staining is often required to image a cell that is adherent and flat (thin). ✔✔True. Adherent, flat and unstained cells are almost invisible due to the limits on both resolution and contrast. Therefore, cell staining is often required to adequately image the samp Which of the following could NOT be seen clearly by the unaided eye? Select all that apply. ✔✔24um and 0.2um. The unaided eye can, on average, clearly resolve objects > 100 μm This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects. ✔✔Fluorescence This type of microscope uses a specialized condenser and objective to amplify the slight differences between cells and background ✔✔Phase-Contrast his type of microscope enhances contrast between specimen and background but does not permit the visualization of intracellular structures ✔✔Dark Field This type of microscope uses neither halogen nor UV light sources but rather lasers to illuminate stained cells in high resolution ✔✔Confocal

You suspect a patient may have TB. Once a sample has been obtained it is sent off to the lab for an acid-fast stain. If the patient were infected with TB, describe what you would expect to see on the stained slide. ✔✔You would expect to see red cells (TB+) on a blue background (TB negative). true or False: If a patient is suspected of having malaria, a Giemsa stain would be an appropriate differential test to perform. ✔✔True. Giemsa stains are often used in the clinical setting to aid in the diagnosis of blood parasites. Define the measurements micrometer and nanometer. ✔✔A micrometer (μm) is defined as being one-millionth of a meter and is commonly designated at 10- 6 meters. A nanometer (nm) equals 10 - 9 m or one-billionth of a meter. What are the two critical factors that influence your ability to see an object? ✔✔Resolution and contrast. Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one. The contrast is the difference in light absorbance between two objects. Poor contrast gives a high background and makes the visualization of multiple objects difficult. For instance, trying to identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against 2 dark objects = high contrast).

As light passes through a microscope, what is the last piece that light passes before reaching your eyes? ✔✔Once light passes through the sample and the objective lens it is directed through the ocular lens, or eyepiece, directly into your eye. What is one limitation of fixing your sample? ✔✔Fixation requires you to irreversibly kill your sample. Thus, determining the motility (cell movement) of a sample is impossible. Fixation also runs the risk of distorting the specimen shape and arrangement. Phase-contrast microscopy provided what benefits to imaging? ✔✔Phase contrast microscope can provide detailed images of live cells without staining. By using specialized condensers and objectives, a phase contrast microscope amplifies the slight differences between cells and the surrounding medium (background) to make the cells highly distinguishable. What is the distinguishing feature of dark field microscopy? ✔✔Unlike bright field or phase contrast microscopy where light passes directly through the sample, dark field microscopy reflects light off of the specimen at an angle. The resulting image is an exceptionally dark background and a vibrant specimen. Unlike brightfield microscope, fluorescence microscopes illuminate samples through what spectrum? ✔✔The energy of the incoming light is in the form of the ultraviolet (UV) spectrum.