Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

DIM > Lecture12 > Flashcards

Lecture12 Flashcards

(111 cards)

Start Studying
1
Q

What type of microscope is primarily discussed in the text?

A

Transmission electron microscope

透射电子显微镜

The text also briefly mentions scanning electron microscopes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is essential for the operation of a transmission electron microscope?

A

Vacuum

The operation requires a vacuum to prevent interference from air molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the purpose of contrast agents in electron microscopy?

电子显微镜中造影剂的用途是什么？

A

To enhance electron density visibility

增强电子密度可见性

Common agents include lead citrate and uranyl acetate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What types of materials are typically used as contrast agents?

A

Heavy metals

Examples include osmium tetroxide, lead, and uranium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the required thickness of sections for transmission electron microscopy?

A

Angstrom range

Very thin sections are necessary to allow electron beams to pass through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to samples during imaging in an electron microscope?

A

They must be embedded in resin and dehydrated

This prevents samples from burning due to the intense electron beam.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the role of the electron gun in a transmission electron microscope?

A

To produce the electron beam

The electron beam is essential for imaging specimens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a diamond knife used for in electron microscopy?

A

To cut very thin sections from samples

Diamond knives are preferred for their hardness.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What must be done to the samples before using a transmission electron microscope?

A

Dehydrate and embed them

This is necessary to prepare them for vacuum conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the typical magnification range for electron microscopy?

A

5,000 to 25,000 times

Higher magnifications can be achieved for detailed structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

True or False: Live materials can be observed directly in a transmission electron microscope.

A

False

Live materials cannot be observed due to the vacuum requirement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What technology is used in modern electron microscopes for image capture?

A

CCD cameras

CCD cameras allow for faster image capture compared to film.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the typical range of resolution achievable by electron microscopy?

A

5 to 20 nanometers

The theoretical limit can reach the picometer range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Fill in the blank: The electron beam in a transmission electron microscope interacts with the sample to cast a ______.

A

shadow

The shadow shows the electron density of the specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What types of grids are used in electron microscopy?

A

Single slot grids, honeycomb grids

Different grids help in specimen orientation and support.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does colloidal gold contribute to electron microscopy?

A

It enhances contrast for specific proteins

Colloidal gold binds to antibodies for specific labeling.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the primary disadvantage of electron microscopy?

A

Samples must be fixed and dehydrated

This limits the types of samples that can be observed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the significance of the art of sectioning in electron microscopy?

A

It requires precision and stability to produce thin sections

Proper technique is crucial for successful imaging.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to the electron beam during imaging?

A

It can burn through the specimen holder

This necessitates frequent sample changes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the theoretical limit of electron microscopy?

A

In the picometer range

This allows for observation at a molecular level.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What type of microscopy is commonly used to reveal the ultra structure of viruses?

A

Electron microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is required for electron microscopy to function?

A

Specimens must be in vacuum and fixed without water content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

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

A

TEM transmits an electron beam through the sample, while SEM scans the surface of the specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the purpose of a gold layer in SEM?

A

To reflect electrons and enhance imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
True or False: Scanning electron microscopy can provide information about the material composition of a specimen.
True
26
What is the Stoke shift in fluorescence?
The difference between the excitation wavelength and the emission wavelength
27
Fill in the blank: In fluorescence microscopy, a _______ is the molecule that gets excited and emits light.
fluorophore
28
What light sources are typically used in conventional fluorescence microscopy?
Mercury or xenon lamps
29
What is the role of a dichroic mirror in fluorescence microscopy?
To reflect excitation light while allowing emitted light to pass through
30
What type of images does scanning electron microscopy typically produce?
High-resolution images of surface structures
31
What is the main function of filters in fluorescence microscopy?
To select specific wavelengths of excitation and emission light
32
True or False: You can see color in electron microscopy images.
False
33
What happens to electrons in a fluorophore after excitation? | 激发后荧光团中的电子会发生什么变化？
They fall back to a lower energy state and emit light | 它们会回到较低的能量状态并发光
34
What is the typical wavelength relationship in fluorescence microscopy?
Excitation occurs at shorter wavelengths and emission at longer wavelengths | 激发波长较短，发射波长较长
35
What is the purpose of the excitation filter in fluorescence microscopy?
To isolate a specific wavelength of light for excitation | 分离出特定波长的光进行激发
36
Fill in the blank: The imaging path in fluorescence microscopy includes an energy source, a _______ mirror, and an emission filter.
dichroic | 二向色镜
37
What is one of the main advantages of confocal microscopy over traditional fluorescent microscopy? | 与传统荧光显微镜相比，共聚焦显微镜的主要优势是什么？
Higher resolution and the ability to create 3D images
38
What type of microscopy combines both transmission and fluorescence imaging?
Fluorescent microscopy
39
What is the typical color emitted when a fluorophore excited by green light? | 荧光团被绿光激发后通常会发出什么颜色？
Red
40
True or False: The fluorescent signals in microscopy are typically strong.
False
41
What does SEM stand for?
Scanning Electron Microscope
42
What is the range of sizes that electron microscopy can visualize?
From micrometers to nanometers
43
What concept explains why different wavelengths correspond to different energy levels in fluorescence? | 是什么概念解释了为什么不同波长对应不同能级的荧光？
Stoke shift | 斯托克转移
44
What is typically excited with a green line and emits in a lower wavelength, which is red? | 什么物质通常以绿色线激发，并以较低的波长（即红色）发射？
A fluorophore | 一种荧光团 ## Footnote This refers to the process of fluorescence where the initial excitation occurs at a higher energy level and the emission happens at a lower energy level.
45
What is the term for the shift in wavelength from excitation to emission in fluorescence? | 荧光中从激发到发射的波长变化是什么意思？
Stoke shift ## Footnote The Stoke shift is the difference in wavelength between the absorbed light and the emitted light.
46
What type of microscopy requires specific filters to visualize fluorescence channels?
Fluorescence microscopy ## Footnote Filters are necessary to isolate specific wavelengths of emitted light from the fluorophores.
47
What is a common drawback of fluorescent imaging?
Fluorescence quenching and bleaching | 荧光淬灭和漂白 ## Footnote These processes can diminish the signal and alter the molecules, leading to loss of fluorescence.
48
What kind of filter allows only a specific band of wavelengths to pass through?
Band pass filter ## Footnote Band pass filters are crucial in fluorescence microscopy to isolate the desired emission wavelengths.
49
What is the function of a dichroic mirror in fluorescence microscopy? | 二向色镜在荧光显微镜中的作用是什么？
It reflects excitation wavelengths and allows emission wavelengths to pass through ## Footnote The dichroic mirror is essential for separating the excitation light from the emitted fluorescence.
50
What are typical excitation sources in fluorescence microscopy?
* Mercury lamps * Xenon lamps * Lasers | * 汞灯/氙气灯/激光 ## Footnote These sources provide the necessary light for exciting fluorophores.
51
Fill in the blank: Fluorophores typically contain _______ groups. | 荧光团通常含有_______基团。
aromatic | 芳香族基团 ## Footnote Aromatic groups are responsible for the ability to absorb and emit light.
52
What is the purpose of phase contrast microscopy?
To produce diffraction patterns in unstained materials | 在未染色的材料中产生衍射图案 ## Footnote Phase contrast microscopy enhances contrast in transparent specimens without staining.
53
What Nobel Prize-winning scientist contributed to the development of phase contrast microscopy?
Fritz Zernike ## Footnote Zernike was awarded the Nobel Prize for his work in developing this microscopy technique.
54
What happens during constructive interference in phase contrast microscopy? | 相差显微镜中的建设性干涉期间会发生什么？
Brighter objects appear on a darker background ## Footnote This occurs due to the phase shift of light waves interacting with the specimen.
55
What is a negative phase contrast image?
An image where dark objects appear on a light background ## Footnote This result from destructive interference of light waves.
56
How do fluorescent stains help in microscopy? | 荧光染色对显微镜检查有何帮助？
They bind to specific structures, allowing visualization of nuclei and other components | 它们与特定结构结合，使细胞核和其他成分可视化 ## Footnote Common stains include DAPI, which binds to DNA.
57
What is necessary for a microscope objective to perform phase contrast?
A phase plate within the objective | 物镜内的相位板 ## Footnote This modification is essential for producing the phase shift needed for contrast.
58
What is the effect of using a higher numerical aperture in microscopy?
Increased light gathering ability, resulting in better image quality | 聚光能力增强，图像质量更好 ## Footnote Higher numerical apertures allow for more light to enter the microscope.
59
What is the significance of integrating longer in fluorescence microscopy? | 荧光显微镜中积分时间延长有何意义？
It compensates for low fluorescence intensity | 它补偿了低荧光强度 ## Footnote Longer integration times help capture clearer images when fluorescence is weak.
60
What is the role of filters in fluorescence microscopy?
To isolate specific wavelengths of light for excitation and emission ## Footnote Filters ensure that only the desired wavelengths are used to visualize the specimen.
61
Who was instrumental in developing the confocal microscope?
Key figures include Focal Markus, Wilson, Denck, and Aaron Davidovits ## Footnote Marvin Minsky also contributed to the principles behind confocal microscopy.
62
What is the key principle of the confocal microscope?
The pinhole reduces the depth of focus to capture only one particular focal layer | 针孔减少了焦深，只捕捉一个特定的焦点层 ## Footnote This contrasts with conventional fluorescence microscopy, which captures a broader range of focal planes.
63
What does the emission pinhole do in a confocal microscope?
It blocks out-of-focus light, allowing only in-focus light to pass through | 它阻挡了失焦的光线，只允许焦距内的光线通过 ## Footnote This enhances image clarity by focusing on a specific focal plane.
64
What type of light source is used in confocal microscopy?
A laser, which provides monochromatic light | 提供单色光的激光器 ## Footnote This is different from conventional microscopy, which may use white light sources like arc lamps.
65
What is the difference in imaging between confocal and conventional fluorescence microscopes? | 共聚焦显微镜和传统荧光显微镜的成像有何不同？
Confocal microscopes provide higher resolution and a clearer image by focusing on one focal plane ## Footnote In contrast, conventional microscopes may have a larger focal range resulting in blur.
66
How does the pinhole size affect resolution in confocal microscopy?
Smaller pinholes yield higher resolution, while larger pinholes decrease resolution ## Footnote This is due to the relationship between pinhole size and the Airy disk.
67
What is the effective resolution of wide field microscopy?
Approximately 1.2 microns ## Footnote Confocal microscopy can improve this to about 0.4 microns due to its pinhole architecture.
68
What is deconvolution in microscopy?
It is a computational method to remove out-of-focus contributions from images | 这是一种从图像中消除失焦影响的计算方法 ## Footnote This enhances image clarity by using the characteristics of the optical setup.
69
What are some specific applications of fluorophores in confocal microscopy?
Fluorophores can be specific to amino acids, lipids, nucleotides, and can be used in immunohistochemistry | 荧光团可以特异性地针对氨基酸、脂质、核苷酸，并可用于免疫组织化学 ## Footnote They can also be utilized with transgenic specimens like GFP.
70
What is the role of the photo multiplier in confocal microscopy? | 光电倍增管在共聚焦显微镜中起什么作用？
It amplifies the signal after emission to produce a clear image ## Footnote This is necessary due to the weaker signal in confocal microscopy compared to standard fluorescence microscopy.
71
What advantages does confocal microscopy have over conventional microscopy?
Increased effective resolution, improved signal-to-noise ratio, and the ability to create 3D images ## Footnote Confocal microscopy allows for non-destructive imaging of live samples.
72
What scanning technique is used in confocal laser scanning microscopy?
A scanning laser point moves over the sample to measure emission at each point ## Footnote This is facilitated by a Galvano mirror that directs the laser.
73
Fill in the blank: Confocal microscopy allows for _______ imaging by shifting the focal plane.
3D
74
True or False: Confocal microscopy can visualize only one focal plane at a time.
True
75
What is the significance of using multiple laser lines in confocal microscopy?
Different laser lines can excite different fluorophores, allowing for multicolor imaging ## Footnote This enables detailed analysis of complex samples.
76
What is a common fluorophore used in confocal microscopy for visualizing proteins?
Green fluorescent protein (GFP) ## Footnote GFP is often used in transgenic organisms to study gene expression.
77
What is the cytoskeleton? | 什么是细胞骨架？
The inner part of a cell that provides structural support.
78
What does a volume image represent?
A three-dimensional representation of a specimen.
79
What is a projection in confocal microscopy?
Combining all confocal layers into one image.
80
What is a key shortcoming of imaging in the z direction?
Sampling in the z direction is often lower than in the x-y direction.
81
What is bioluminescence?
Light produced by an organism through a chemical reaction.
82
What is biofluorescence?
Light produced by an organism when excited by an external light source. | 71 / 5,000 生物体受到外界光源刺激时产生的光。
83
What is green fluorescent protein (GFP)?
A protein used as a reporter gene to visualize gene expression.
84
What is the main advantage of multi-photon microscopy?
Deeper penetration into the specimen with lower energy photons.
85
What is the difference between confocal and multi-photon microscopy?
Multi-photon uses lower energy photons for deeper penetration and localized excitation.
86
What is required for live imaging with multi-photon microscopy?
Stable conditions including temperature control and multiple laser systems.
87
What is deconvolution in imaging?
A technique to compensate for lens flaws and improve image clarity.
88
What is tomography? | 什么是断层扫描？
Reconstructing a 3D object from multiple 2D views.
89
What is the purpose of image reconstruction?
To create a representation as close as possible to the real 3D object.
90
Fill in the blank: GFP is extracted from the _______.
jellyfish.
91
True or False: Multi-photon microscopy requires higher energy light than confocal microscopy.
False.
92
What is the excitation maximum of GFP?
It has two maxima.
93
What are the advantages of using lower energy photons in multi-photon microscopy?
* Less damage to the specimen * Deeper penetration.
94
What is a common use for confocal microscopy?
Imaging specific structures within a cell.
95
What is a significant challenge in confocal microscopy?
Out-of-focus light contributing to haziness in images. | 失焦的光线导致图像模糊。
96
What does the term 'fusion proteins' refer to?
Proteins that have been genetically engineered to include GFP or other fluorescent markers.
97
What is the role of the promoter in relation to GFP?
It activates gene expression and the production of GFP.
98
What is the process of image restoration?
Improving the quality of an image to resemble the real scene.
99
Fill in the blank: The femto laser is used in multi-photon microscopy to deliver _______.
short pulses of low energy photons. | 低能光子的短脉冲。
100
What is image reconstruction?
Image reconstruction is the process of attempting to recreate the original signal as closely as possible to the real scene.
101
What is the goal of reconstruction in the context of 3D objects?
To be as close as possible to what the 3D object looks like.
102
What is a Z stack?
A Z stack is a series of images taken at different depths (Z direction) through a specimen.
103
In which planes is the sampling multiplied for reconstruction?
In the x, y, and z planes.
104
What is the purpose of reconstruction in imaging?
To visualize the sampled data accurately and make measurements.
105
What is required to perform effective reconstruction?
A lot of implicit knowledge about the sample and the imaging process.
106
Fill in the blank: Implicit knowledge is crucial for reconstruction because it helps to understand the _______.
[sampling parameters and signal intensity]
107
What does the intensity of the signal indicate in reconstruction?
It indicates the strength of the signal captured from consecutive planes.
108
True or False: The planes used in reconstruction must always be parallel.
False.
109
What is a necessary condition for using a different reconstruction technique?
If the planes are oriented at an angle.
110
What is one advantage of using zebrafish embryos in imaging studies?
Zebrafish embryos are transparent, allowing deeper signal capture.
111
What type of signal is typically looked at in a Z stack using confocal or multi-photon techniques? | 使用共焦或多光子技术在 Z 堆栈中通常观察哪种类型的信号？
The fluorescent signal. | 荧光信号

DIM (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions