Microscopy

Question 1

Thinnest picture is by

Answer 1

Scanning Electron Microscopy

Question 2

Light microscope kind

Answer 2

1- phase contrast
2- fluorescence microscope

Question 3

Electron microscopes kind

Answer 3

1- transmission electrons
2- scanning electrons

Question 4

Three elements needed for imaging

Answer 4

1- source of illumination
2- speciemen to be examined
3- system of lenses

Question 5

Condenser lens

Answer 5

In front of light source

Question 6

Objective lens

Answer 6

Closest lense to object

Question 7

Ocular lens

Answer 7

Magnify image created by objective lense

Question 8

Magnification

Answer 8

Size of the image vs object

Question 9

Empty magnification

Answer 9

Maginified without resolution

Question 10

Resolving power is

Answer 10

Resolution

Question 11

Resolution allows object to

Answer 11

Be distinguished

Question 12

Resolution

Answer 12

Minimum distance two points can be apart and remain apart

Question 13

Magnification consider

Answer 13

1- refraction index of lens
1- medium that sample is immersed in
2- focal length of lens

Question 14

Resolution considers

Answer 14

1- wavelength of illumination
2- refraction index
3- angular aperture

Question 15

Longer wavelength

Answer 15

Larger object observed

Question 16

Shorter wavelength

Answer 16

Smaller object obseved

Question 17

Abbe equation

Answer 17

r=0.61landa/nsin(alpha)

Question 18

Magnification in air and oil

Answer 18

1000 and 1400

Question 19

Lighting

Answer 19

How light reflects off an object

Question 20

Contrast

Answer 20

Difference in appearance between object and its background

Question 21

Bright field microscopy

Answer 21

Light microscope
White light passed through specimen
Living sample are nearly invisible
Better image if stained:fixed

Question 22

Bright field stain

Answer 22

Stain with dye absorb specific wavelength
Different dye for different biomolecules

Question 23

Phase contrast

Answer 23

Light microscope
Use differences in refractive index and thickness
Without the need to section/stain
Turn Phase differences to brightness

Question 24

Differential Interference Contrast

Answer 24

Shadow-casting effect
Cells dark on one side
Light on the other side
3D image

Question 25

Fluorescence Microscopy

Answer 25

Detect fluorescent proteins Use laser beam to illuminate a single plane of fluorescently

Question 26

Excitation is ——— wavelength than emission

Answer 26

Smaller/shorter

Question 27

Excitation filters

Answer 27

Transmit only light of particular wavelengths

Question 28

Dichroic mirror

Answer 28

Reflect light below a certain wavelength

Question 29

Emission filter

Answer 29

Prevent light from exiting microscope

Question 30

Immunostaining uses ——— to locate specific molecules

Answer 30

Antibidies

Question 31

Immunofluorescence microscopy advantage

Answer 31

-high specifity -string signal -identifies proteins in their native environment

Question 32

Immunofluorescence microscopy disadvantage

Answer 32

Experiment on dead cell Might not be any available antibody

Question 33

GFP

Answer 33

Green Fluorescent Protein

Question 34

GFP advantage

Answer 34

Cellular events in living cell

Question 35

GFP disadvantaged

Answer 35

Introducing the gfp-tagged protein

Question 36

Confocal fluorescence microscopy

Answer 36

Optical sectioning: produce in-focus images 3D reconstruction Distinguish structures in the middle of the cell from top and bottom

Question 37

Advantage of fixed cells

Answer 37

1- sectioning thick tissue 2- easier to manage samples 3- no need to recombinant protein

Question 38

Advantage of live cell

Answer 38

1- movement of biomolecules within a cell 2- critical context to your observation

Question 39

Electron microscope

Answer 39

Use of beam of electrons and electromagnets

Question 40

Electron microscope types

Answer 40

1- scanning electron microscopes 2- transmission electron microscope

Question 41

Scan electron microscopes

Answer 41

Surface is scanned Detecting electrons from outer surfaces

Question 42

Transmission electrons microscope

Answer 42

Electrons are transmitted through the specimen

Question 43

Cryo-Et microscopy

Answer 43

Take multiple 2D images at different angles and crrate a 3D reconstruction

Question 44

Fluorrescense recovery after photobleaching (FRAP)

Answer 44

Measure how fast a molecule moves (Bleach an area and see how long takes for unbleached molecules to return)

Question 45

Fluorescense Resonance Energy Transfer (FRET)

Answer 45

Measure if two molecules are touching (If closer than 10nm one can excite other)