BIOD 171 Module 3 Exam Practice Questions

This type of microscope can provide detailed images of live cells without staining.

This type of microscope is used to greatly increase the contrast between samples and background by reflecting light off of the specimen.

This type of microscope uses neither halogen nor UV light sources but rather lasers to illuminate stained cells in high resolution.

Identify what type of electron microscope was used to capture the following image and explain your choice.

Gram-Positive cells appear [answer1] in color due to a [answer2] peptidoglycan layer in the cell wall.

Gram-Negative cells appear [answer1] in color due to a [answer2] peptidoglycan layer in the cell wall.

True or False: The distinguishing characteristic of Gram-Negative bacteria is the presence of LPS in the outer membrane.

Name one substance capable of chemically fixing cells to a slide.

You want to observe the size and shape of a cell. What is the easiest staining technique that you could perform? Name at least one dye you would use during this process.

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.

True or False: A Giemsa stain can be used to determine the presence of pathogenic bacteria.

Identify what type of electron microscope was used to capture the following image and explain your choice.

What is the main advantage of using a phase-contrast microscope?

Describe the purpose of the condenser lens in a microscope.

What is the role of immersion oil in microscopy?

Which staining technique would you use to differentiate between Gram-positive and Gram-negative bacteria?

True or False: Electron microscopes use light to visualize specimens.

What is the difference between a simple stain and a differential stain?

What is the purpose of heat-fixing a bacterial smear before staining?

Name one advantage of using a confocal microscope over a traditional fluorescence microscope.

Why is it important to use a thin smear when preparing a slide for microscopic examination?

What type of microscopy would you use to observe the detailed surface structure of a specimen?

True or False: Differential interference contrast (DIC) microscopy is similar to phase-contrast microscopy but provides a 3D-like image.

What is the primary function of the iris diaphragm in a microscope?

Describe the appearance of Gram-negative bacteria after a Gram stain.

What is the significance of using a mordant in the Gram staining process?

True or False: Dark field microscopy is ideal for observing transparent or unstained specimens.

Name one application of fluorescence microscopy in biological research.

What is the main limitation of using bright field microscopy for observing live cells?

Which type of microscopy would you use to observe the internal structure of a cell at high resolution?

True or False: The coarse adjustment knob is used for fine focusing at high magnifications.

Describe the appearance of acid-fast bacteria after an acid-fast stain.

What is the purpose of using a counterstain in the Gram staining procedure?

Which type of microscopy would you use to observe the motility of live bacteria?

True or False: The resolving power of a microscope is determined by the wavelength of light used and the numerical aperture of the objective lens.

What is the main advantage of using a scanning electron microscope (SEM) over a transmission electron microscope (TEM)?

Describe the process of preparing a bacterial smear for Gram staining.

Name one dye commonly used in a simple stain.

True or False: Confocal microscopy can be used to create high-resolution, 3D images of specimens.

What is the primary purpose of using a decolorizer in the Gram staining process?

Describe the appearance of Gram-positive bacteria after a Gram stain.

Which type of microscopy would you use to observe fluorescently labeled molecules within a cell?

True or False: The fine adjustment knob is used for focusing at low magnifications.

What is the purpose of using a cover slip when preparing a slide for microscopy?

Which staining technique would you use to identify Mycobacterium tuberculosis in a clinical sample?

Describe the appearance of non-acid-fast bacteria after an acid-fast stain.

True or False: The numerical aperture (NA) of an objective lens affects the resolution of a microscope.

What is the main advantage of using a dark field microscope?

Describe the role of the objective lens in a microscope.

Which type of microscopy would you use to observe the detailed internal structure of a virus?

True or False: Gram-positive bacteria have a thicker peptidoglycan layer than Gram-negative bacteria.

What is the purpose of using a mordant in the Gram staining process?

Describe the appearance of Gram-negative bacteria after a Gram stain.

Which type of microscopy would you use to observe the surface structure of a specimen at high magnification?

True or False: The coarse adjustment knob is used for initial focusing at high magnifications.

Describe the process of preparing a bacterial smear for acid-fast staining.