Q: Which equation correctly describes the relationship between resolution, wavelength, and numerical aperture in light microscopy?

$$\text{resolution} = \frac{0.61 \lambda}{n \sin \theta}$$

Question 1

Which factor would most improve the resolution of a light microscope according to the formula $$	ext{resolution} = \frac{0.61 \lambda}{n \sin 	heta}$$?

Accepted Answer

Increasing the refractive index ($$n) of $$the medium

Question 2

A researcher wants to visualize the distribution of a specific mRNA within a tissue section. Which technique should they use?

Accepted Answer

In-situ hybridization

Question 3

Which microscopy technique is best for visualizing unstained, living cells and highlights edges by combining out-of-phase light waves?

Accepted Answer

Phase-contrast or differential interference contrast (DIC) microscopy

Question 4

What is the primary purpose of using glutaraldehyde in sample preparation for microscopy?

Accepted Answer

To cross-link proteins and stabilize tissue structure

Question 5

Which of the following statements about fluorescence microscopy is correct?

Accepted Answer

Fluorophores absorb light at a specific wavelength and emit light at a longer wavelength

Question 6

A scientist wants to determine if two proteins are physically close together in a cell. Which technique should they use?

Accepted Answer

Fluorescence resonance energy transfer (FRET)

Question 7

Which microscopy technique allows for deeper tissue penetration and minimal tissue damage by using lower-energy light?

Accepted Answer

Two-photon excitation microscopy

Question 8

What is the main advantage of confocal microscopy compared to traditional fluorescence microscopy?

Accepted Answer

It excludes out-of-focus light to produce optical sections

Question 9

Which of the following is NOT a property of lipid rafts in biological membranes?

Accepted Answer

They are composed mainly of unsaturated lipids

Question 10

If the flip-flop movement of membrane lipids is inhibited, what is the most likely consequence?

Accepted Answer

Lipid distribution between leaflets will become asymmetric

Question 11

Which equation correctly describes the relationship between resolution, wavelength, and numerical aperture in light microscopy?

Accepted Answer

$$	ext{resolution} = \frac{0.61 \lambda}{n \sin 	heta}$$

Question 12

Which microscopy technique is best suited for visualizing molecules located very close to the surface of a specimen, such as membrane proteins?

Accepted Answer

Total internal reflection fluorescence microscopy (TIRF)

Question 13

What is the main difference between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)?

Accepted Answer

SEM produces 3D images by detecting electrons bouncing off the surface, while TEM produces 2D images by detecting electrons passing through the specimen

Question 14

Which step is NOT part of the standard preparation of biological specimens for transmission electron microscopy (TEM)?

Accepted Answer

Staining with fluorescent dyes

Question 15

Which property of amphipathic lipids allows them to spontaneously form bilayers, micelles, and liposomes?

Accepted Answer

Their polar and nonpolar regions interact differently with water

Question 16

What effect does cholesterol have on membrane fluidity at high temperatures?

Accepted Answer

It decreases membrane fluidity

Question 17

Which movement of membrane lipids is least likely to occur spontaneously and requires enzymes such as flippases?

Accepted Answer

Flip-flop movement

Question 18

A cell membrane is found to have glycolipids and carbohydrates facing the extracellular side. What is the primary function of this asymmetry?

Accepted Answer

To facilitate cell-cell recognition and protect the cell from the environment

Question 19

Which technique uses antibodies linked with gold molecules to provide contrast and label surface antigens in electron microscopy?

Accepted Answer

Immunogold EM

Question 20

What is the main advantage of single-particle reconstruction in electron microscopy?

Accepted Answer

It creates near atomic resolution by digitally aligning thousands of noisy images of identical molecules

Microscopy and Membrane Structure: Principles and Applications

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