Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology - Eukaryotes > Microscopy > Flashcards

Microscopy Flashcards

1
Q

What three parameters define microscopy?

A

Magnification
Resolution
Contrast

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

Magnification

A

This describes ratio of an objects image size to its real size

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

Resolution

A

This is the measure of the minimum distance of two distinguishable points

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

Contrast

A

Visible differences in brightness of color between parts of the sample.

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

What is the most commonly used microscope?

A

Bright Field Microscope

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

Bright Field Microscope

A

These are the simplest where illumination light is transmitted through the sample and the contrast generated by absorption of light in dense areas of the specimen

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

What are the types of light microscope?

A

Bright Field Miscroscope
Fluoresence Microscope
Phase/Differential Contrast
Confocal Microscope

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

Fluoroesence Microscope

A

This is an imaging technique visualing fluoresence from analyzed material with fluorophore excitation

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

What is the highest resoloution of light microscopy?

A

0.2 Microns

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

What is the light source for LM?

A

Halogen Lamp or LED emitting broad weavelength spectrum focused onto specimen by a condenser

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

Condenser

A

This serves to gather wavefronts from the microscope light source and concentrat them into a cone of light illuminating the specimen with uniform intensity

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

How is the specimen magnified?

A

Objective lense

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

Iris Diaphragm

A

This regulates numerical aperture, influencing resolution and contrast of the image.

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

What magnisifes the imagine fomred by the optical lense?

A

Ocular Lense then a tube lens

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

What does formation of final image depend on?

A

Absorption, reflection and scattering of light

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

How can contrast be improved?

A

Use light phase shifts induced by the specimen

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

Phase Contrast

A

This is a technique used for gaining contrast in a translucent specimen without staining it

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

Differential Interference Contrast

A

This is a technique based on an interference principle involving two coherent beams of light from the same source with image gradients by optical path gradients.

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

What is the sample preparation procedure for LM?

A

Tissues require sectioning
Fixation
Dehydration and cleaning
Specimen embedded into molten max
Microtome seconted into 5 micron thick
A colour dye is added

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

Why is fixation important?

A

Tissue structural preservation

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

Confocal Microscopy

A

This is a fluoresence imaging technique generating 3D images of living cells removing out-of-focus images

22
Q

Galvanometer Mirors

A

This is an ammeter indicating sensing of electric currents by deflection of light beams with a mirror.

23
Q

How does Confocal Microscopy work?

A

Emits a laser with monochromatic light for high-intensity illumating scanning specimen using galvanometer mirrors

24
Q

Focal Plane

A

This is a plane perpendicular to the axis of a lens or mirror and passing through the focus.

25
Q

Optical Sectioning

A

This is the process where a suitably deisgned microscpe can produce clear images of focal planes deep within a thick sample.

26
Q

What are more modern techniques of microscopy?

A

Deconvolution microscopy
Super resolution

27
Q

Deconvolution Microscopy

A

This is used to improve contrast/resolution of images captured in an optical microscope

28
Q

Super Resolution

A

This allows imaging of structures at resolutions beyond the diffraction limit of light

29
Q

How does deconvolution microscopy work?

A

Reversing optical blur formed by point-spread functions

30
Q

Point-Spread Functions

A

This describes how a point source of light spreads out as it passes thorugh the optical system forming an image.

31
Q

Electron Microscopes

A

This use beams of electrons instead of light to visualise electrons with higher resoloution due to the smaller wavelenght

32
Q

How much more resolute is EM?

A

1000x better

33
Q

How do EM work?

A

Thermionic emission gun emits electrons from heated filaments accelrated and focused by electric fields created by electrodes

34
Q

What is the lens strucure of EM?

A

Series of magnetic field generating coils interacting with charge and momentum of the electron, condenser, objective and projectior

35
Q

How do electrons interact with the sopecimen?

A

Formation of diffraction patterns by scattering, electron loss/excitation of energy transfer to the specimen, secondary electorn emission

36
Q

Why are EM kept in a vaccum?

A

Presence of gas molecules may perturb electron scattering/asborptions

37
Q

What are the two types of EM?

A

Transmission
Scanning

38
Q

Transmission Electron Microscopes

A

These use tungesten-based electron guns to grnerate images based on electrons passing through the specimen

39
Q

Thermionic Emission

A

This is the flow of charged particles called thermions from charged metals/metal oxides caused by vibrational energy overcoming electrostatic forces holding electrons to the surface

40
Q

How are TEM samples fixated?

A

Glutaraldehyde then Osmium tetroxide

41
Q

How do Glutaraldehyde and Osmium tetroxide work?

A

Covalenelty cross-link protein AA and provide contrast to samples by lipid covalent linkage

42
Q

Ultramicrotome

A

This is a method for cutting specimens into extremely thin slices called ultra-thin sections

43
Q

How is contrast improved in TEM?

A

Heavy metal stains like lead

44
Q

Scanning Electron Microscope

A

This is where low energy electron beams scan the surface of a sample

45
Q

How does SEM work?

A

Leads to sample interactions reflected and collected by a detector converting into electronic signals displayed on a screen, providing representation of topology.

46
Q

Critical Point Drying

A

This is a method of drhydrating biological tissue prior to SEM for removal of ethanol to minimise shrinkage

47
Q

Cell Fractionation

A

This is a technique of seperation of cellular organelles for study in isolation

48
Q

How is cell fractionation done?

A

Homogenization of the cell
Differential Centrifugation of organelles

49
Q

Homogenization

A

This is the mechanical disruption by shear force generation with mechanical action to release cellular components into a homogenate

50
Q

Differential Centrifugation

A

This is seperation of the cellular components bsaed on size, density, by spinning the clel at various speeds.

51
Q

Differential Centrifugation

A

This is seperation of the cellular components bsaed on size, density, by spinning the clel at various speeds.

Biology - Eukaryotes (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions