Q: Which equation correctly relates the resolving power ($d$) of a light microscope to the wavelength ($\lambda$) of light and the numerical aperture (NA)?

$d = \frac{0.61 \times \lambda}{NA}$

Question 1

Which of the following best describes the main advantage of phase contrast microscopy over bright field microscopy when imaging live cells?

Accepted Answer

It increases contrast in transparent specimens without the need for staining.

Question 2

A researcher wants to visualize the localization of two different proteins within the same cell. Which microscopy technique and labeling strategy should they use?

Accepted Answer

Fluorescence microscopy with two antibodies conjugated to different fluorophores.

Question 3

Which equation correctly relates the resolving power ($d$) of a light microscope to the wavelength ($\lambda$) of light and the numerical aperture (NA)?

Accepted Answer

$d = \frac{0.61 	imes \lambda}{NA}$

Question 4

Which of the following statements about fluorescence microscopy is CORRECT?

Accepted Answer

It relies on the excitation of fluorophores at one wavelength and emission at a longer wavelength.

Question 5

A scientist is using immunofluorescence to detect a specific protein in a cell. Which component is directly responsible for the specificity of the detection?

Accepted Answer

The antigen-binding site of the antibody.

Question 6

Which of the following is a key advantage of using monoclonal antibodies in cell imaging?

Accepted Answer

They are produced by a single B-cell clone and are highly specific.

Question 7

Why is electron microscopy able to achieve higher resolution than light microscopy?

Accepted Answer

Electrons have a much shorter wavelength than visible light.

Question 8

Which of the following best describes the difference between TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy)?

Accepted Answer

TEM images are based on electrons transmitted through the sample, while SEM images are based on electrons scattered from the surface.

Question 9

A sample is rapidly frozen and imaged at ultra-low temperatures to preserve its native structure. Which imaging technique is being used?

Accepted Answer

Cryo-electron microscopy (Cryo-EM)

Question 10

Which of the following is a limitation of light microscopy compared to electron microscopy?

Accepted Answer

Light microscopy has lower resolution due to the longer wavelength of light.

Question 11

A researcher wants to determine the subcellular localization of a protein in a living cell. Which technique would be most appropriate?

Accepted Answer

Fluorescence microscopy using a fluorescent protein fusion

Question 12

Which property of fluorescent proteins makes them especially useful for live-cell imaging?

Accepted Answer

They can be genetically encoded and expressed in living cells.

Question 13

Which of the following best explains why X-ray diffraction is useful in cell biology?

Accepted Answer

It provides high-quality crystals of molecules for atomic structure determination.

Question 14

A scientist is imaging a cell using fluorescence microscopy and notices that the image is blurry. Which adjustment is most likely to improve the focus?

Accepted Answer

Adjust the fine focus knob to bring the sample into the focal plane.

Question 15

Which of the following is a real-world application of immunofluorescence microscopy?

Accepted Answer

Determining the localization of viral proteins in infected cells.

Question 16

Which of the following statements about the excitation and emission of fluorophores is correct?

Accepted Answer

Emission occurs at a longer wavelength than excitation.

Question 17

Why is it important to use antibodies that specifically target your protein of interest in immunofluorescence experiments?

Accepted Answer

To ensure that the observed fluorescence accurately represents the location of the target protein.

Question 18

Which of the following best describes the principle behind DIC (Differential Interference Contrast) microscopy?

Accepted Answer

It uses differences in refractive index to enhance contrast in transparent specimens.

Question 19

A researcher wants to visualize the 3D surface structure of a cell. Which microscopy technique should they use?

Accepted Answer

Scanning electron microscopy (SEM)

Question 20

Which of the following is a limitation of using immunofluorescence to study protein localization?

Accepted Answer

It typically requires fixation, which prevents imaging of live cells.

Cell Imaging Techniques: Light, Fluorescence, and Electron Microscopy

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