Chapter 9: Assignment Questions COMPLETE Flashcards
Color is a feature of:
objects that are smaller than the wavelength of visible light
objects that are larger than the shortest wavelength of visible light
objects that are larger than the shortest wavelength of visible light
A nanometer (nm) is:
10^-4 meters (m)
10^-9 m
10^-6 m
10^-10 m
10^-9 m
Can light microcopy DETECT an object that is less than 200 nm in diameter?
yes…but the image will be a blur
no
yes…but the image will be a blur
Can conventional light microscopy RESOLVE two objects that are less than 200 nm apart?
yes
no
no
The greater the numerical aperture (n sin theta), the ________ the resolution.
better (i.e. can resolve objects that are closer together)
worse (i.e. objects need to be farther apart to resolve
better (i.e. can resolve objects that are closer together)
Which gives a higher value for “numerical aperture?”
oil
air
oil
The longer the wavelength of the light from a microscope’s light source, the ________ the resolution.
better (i.e. can resolve objects that are closer together)
worse (i.e. objects need to be farther apart to resolve
worse (i.e. objects need to be farther apart to resolve
Noise in a light image refers to:
the numerical aperture
the resolution limit
the wavelength of light
random fluctuations in the distribution of photons that pass through a specimen
random fluctuations in the distribution of photons that pass through a specimen
Which is NOT a good way to visualize living cells?
dark field microcopy
differential interference contrast microscopy
phase contrast microscopy
light microscopy of fixed and stained specimens
light microscopy of fixed and stained specimens
Which is the best (of the following) way to distinguish among different features of a cell?
dark field microcopy
differential interference contrast microscopy
phase contrast microscopy
light microscopy of fixed and stained specimens
light microscopy of fixed and stained specimens
A dye such as hematoxylin that has affinity for negatively-charged macromolecules can reveal the subcellular localization of:
DNA
RNA
proteins with many acidic (negatively charged at physiological pH) side chains
All of those negatively-charged macromolecules listed above
All of those negatively-charged macromolecules listed above
In situ hybridization would best be used to detect specific:
RNAs
DNA
protein
structural carbohydrates
RNAs
In situ hybridization would probably use probes made of:
DNA (because it’s much more stable than RNA)
RNA
protein
DNA (because it’s much more stable than RNA)
Fluorescence microscopy could be used to detect a specific protein if:
the protein of interest has been expressed with a fluorescent domain, such as that of green fluorescent protein
an antibody that specifically binds the protein of interest is attached to a fluorophore (a fluorescent compound)
both of the above!
both of the above!
Generally, the types of fluorescent probes used in fluorescence microscopy:
absorb and emit light in the same wavelength
absorb light and then emit light at shorter wavelength
absorb light and then emit light at a longer wavelength
absorb light and then emit light at a longer wavelength
In fluorescence microscopy, light is generally thought of as being excitation light or emitted light. The light that is absorbed by a fluorophore, leading to its later emission of light is the:
excitation light
emission light
excitation light
In indirect
immunocytochemistry, the “marker molecule” that can lead to detection is attached to:
a primary antibody that directly binds a specific antigen (e.g. protein or other cellular component)
a secondary antibody that binds to a primary antibody that binds a specific antigen
a secondary antibody that binds to a primary antibody that binds a specific antigen
Confocal microscopy produces optical sections of a specimen by
excluding out-of-focus light
using image processing to “deblurr” or “deconvolute” a series of images
excluding out-of-focus light
Which would cause the least amount of damage to a specimen and allow imaging more deeply into the specimen?
ultraviolet light
visible light
infrared light in two-photon applications
infrared light in two-photon applications
In FRET imaging, absorbance of _______ wavelength light by one component of the detection system and transfer of the energy to the second component leads to emission of light of a ___________ wavelength.
shorter; longer
shorter; similar
longer; shorter
longer; similar
shorter; longer
FRET imaging gives a signal if:
the two components are close together
the two components are far apart
the two components are close together
Fluorescence recovery after photobleaching is a way to detect:
proximity of two proteins
movement of tagged proteins or other tagged molecules into the area that had been bleached
3D structure
movement of tagged proteins or other tagged molecules into the area that had been bleached
Which method is used to detect only targets that are very close to the surface of a cover slip?
TIRF
FRAP
image deconvolution
confocal microscopy
FRET
TIRF
Switching fluorophores off and on sequentially in different regions of a specimen over time can lead to pin-point localization of cellular components such as proteins, giving _______ resolution than conventional or confocal fluorescence microscopy.
better
worse
better
The wavelength of an electron in an electron microscope with an accelerating voltage of 100,000 volts is about 0.002 nm. So, visible light with a wavelength of 400 nm has a ___________ longer wavelength than the wavelength of electrons in this example.
10-fold
20-fold
2,000-fold
20,000-fold
200,000-fold
200,000-fold
So, an electron microscope has ___________ resolution than a light microscope.
much better (i.e. resolves objects that are closer together)
much worse
much better (i.e. resolves objects that are closer together)
In practice, the practical resolution of an electron microscope for biological objects is about 1 nm because of:
problems with specimen preparation
contrast with a specimen
damage to the specimen from high-velocity electrons
all of the above
all of the above
So, the practical resolution for electron microscopy is about _________ times better than microscopy using light with a 200 nm wavelength.
200 times!
200,000 times
100,000 times
100,000 times
A beam of electrons travels through a specimen in:
scanning electron microscopy
transmission electron microscopy
transmission electron microscopy
Immunogold microscopy would be appropriate for:
light microscopy
fluorescence microscopy
electron microscopy
confocal microscopy
electron microscopy
Three dimensional images of a specimen can be obtained by:
multiple TEM images taken at slightly different angles and then combined by image processing (EM tomography)
scanning electron microscopy
both!
multiple TEM images taken at slightly different angles and then combined by image processing (EM tomography)
Taking images (maybe thousands) of many identical molecules and then combining them to produce an averaged image is:
single particle reconstruction
scanning electron microscopy
EM tomography
single particle reconstruction
