CH. 9/10: Wrap Up Assignment COMPLETE

Question 1

Detection of presence of a particular mRNA would best be done by:

in situ hybridization
immunohistochemistry
immunogold microscopy
phase contrast microscopy
darkfield microscopy

Answer 1

in situ hybridization

Question 2

Resolution = 0.61 lambda/(n sin theta), where lambda is the wavelength of light used, n is the refractive index of the medium, and theta is half the angular width of the cone of rays collected by the objective lens.

Given this, if everything else stays the same, which gives better resolution as the medium separating the specimen from the objective and condenser lenses?

immersion oil (n = 1.4)
light (n=1)
no difference

Answer 2

immersion oil (n = 1.4)

Question 3

A value of confocal microscopy over conventional fluorescence microscopy is that it:

allows a greater range of fluorescence detection
eliminates out-of-focus light from the image
increases resolution down to 20 nm
can be used with living cells

Answer 3

eliminates out-of-focus light from the image

Question 4

Looking at living cells without stain or a fluorophore would most likely be done by:

bright-field imaging
confocal microscopy
phase-contrast imaging

Answer 4

phase-contrast imaging

Question 5

The functional resolution of electron microscopy is limited to around 1 nm by all of these EXCEPT:

specimen preparation introduces factors that create noise
there’s little contrast in a biological specimen
high velocity electrons could damage the specimen
this resolution limit is based on the minimum electron beam wavelength achievable

Answer 5

this resolution limit is based on the minimum electron beam wavelength achievable

Question 6

Which introduces contrast into electron microscopy imaging:

using a series of different fluorescent proteins
confocal imaging
TIRF
Nomarski imaging
coating with electron-dense ions

Answer 6

coating with electron-dense ions

Question 7

Transmission electron microscopy forms an image from electrons that:

pass through the specimen
reflect off the specimen
induce fluorescence emission
bleach the signal

Answer 7

pass through the specimen

Question 8

The amphipathic lipid monolayer of intracellular lipid droplets is:

formed by engulfment of the lipid with bile salts

formed during endocytosis

formed during exocytosis

derived from the cytosolic leaflet of the endoplasmic reticulum membrane

derived from the non-cytosolic leaflet of the endoplasmic reticulum membrane

Answer 8

derived from the cytosolic leaflet of the endoplasmic reticulum membrane

Question 9

A phospholipid bi-layer can be resolved by:

phase-contrast microscopy
phase-contrast microscopy
confocal imaging
transmission electron microscopy

Answer 9

transmission electron microscopy

Question 10

If the cytosol and the extracellular space were not labeled on a figure, how might you know which side was which?

presence of carbohydrate groups only facing the extracellular fluid

unequal distribution of lipids (e.g. phosphatidylserine on the cytosolic leaflet, etc)

both of the above

Answer 10

both of the above

Question 11

Which is most likely to diffuse laterally freely around a membrane?

a protein that’s in a large protein aggregate

proteins that are tethered to extracellular or intracellular macromolecules

a single-pass transmembrane protein that only has transient interactions with other proteins

cell surface proteins that bind proteins on another cell’s cell surface

a protein that’s penned-in by a cytoskeletal assembly

Answer 11

a single-pass transmembrane protein that only has transient interactions with other proteins

Question 12

A peripheral membrane protein that is covalently linked by a !disulfide bond! to an integral protein of the plasma membrane is in:

the cytosol
the extracellular space
either

Answer 12

the extracellular space