CH. 9: Lecture Questions COMPLETE Flashcards
In a lipid bilayer, which
would polar and/or
charged head groups
face?
A) Aqueous environment
B) Hydrophobic core
A) Aqueous environment
Which is least likely (spontaneously) for a phospholipid?
Rotation
Flip-flip- catalyzed by flippases, scramblases, phospholipid translocases
Lateral Diffusion
Flexion
Flip-flip- catalyzed by flippases, scramblases, phospholipid translocases
In the single-pass
transmembrane
protein show as #4,
the side chains of the
membrane spanning
helix are mostly:
A) Hydrophobic
B) Charged
C) polar
A) Hydrophobic
An amphiphilic (a.k.a.
amphipathic) helix has
A) Mostly
hydrophobic side
chains
B) Hydrophobic side
chains on one side
and hydrophilic
side chains on the
other
B) Hydrophobic side
chains on one side
and hydrophilic
side chains on the
other
The N- and C- termini of the protein
are on ____________ of the
membrane.
A.the same side
B.opposite sides
B.opposite sides
How many oxygen atoms in
the aquaporin channel are
available (i.e. not already
involved in hydrogen bonds)
to attract a proton?
A. All of them
B. None
C. Only the oxygen atom
that’s hydrogen bonded
with the asparagine side
chains
B. None
Spacing of carbonyls on protein side chains underlies ion selectivity It’s more energetically favorable for Na+ to associate with:
A. Water
B. The carbonyls
lining the K+
channel pore
A. Water
Which state
prevents
propagation of an
action potential?
A. Closed
B. Open
C. Inactivated
(refractory)
C. Inactivated
(refractory)
Consider the following for typical ion distribution
across the plasma membrane of a mammalian cell
and a resting membrane potential around 70-80 mV
Which one moves into the cell if a plasma membrane
channel for it is open?
A. Na+
B. K+
C. Cl-
A. Na+
Nuclear proteins, cytosolic proteins, and nuclearly-
encoded mitochondrial proteins are all synthesized in:
A. The cytosol
B. The nucleus
C. The ER
A. The cytosol
The lumen of the ER is topologically equivalent to:
A. The cytosol B. the extracellular space
A. The cytosol
Which causes loading of Sar1 with GTP?
A. GEF
B. GAP
C. GDI
GEF
In this experiment, the N-
terminal fragment of the
protein is only cleaved off when
rough ER microsomes are:
A. Present
B. absent
A. Present
How does a specific protein that catalyzes protein import get to the peroxisome?
A. Insertion into ER membrane; short signal sequence directs vesicular trafficking to
peroxisome
B. C-terminus SKL sequence is an import signal for receptor-mediated uptake of fully-
folded proteins through a translocator into the peroxisome lumen from the cytosol
C. N-term hydrophobic signal sequence also mediates uptake of cytosolic proteins into
the peroxisome membrane or lumen
A. Insertion into ER membrane; short signal sequence directs vesicular trafficking to
peroxisome
How does a Peroxisomal precursor protein get to the peroxisome?
A. Insertion into ER membrane; short signal sequence directs vesicular trafficking to
peroxisome
B. C-terminus SKL sequence is an import signal for receptor-mediated uptake of fully-
folded proteins through a translocator into the peroxisome lumen from the cytosol
C. N-term hydrophobic signal sequence also mediates uptake of cytosolic proteins into
the peroxisome membrane or lumen
B. C-terminus SKL sequence is an import signal for receptor-mediated uptake of fully-
folded proteins through a translocator into the peroxisome lumen from the cytosol
What causes an
importin to release
its cargo?
A. Ran-GDP
B. Ran-GTP
B. Ran-GTP
Which binds tethering proteins?
A. Rab-GTP
B. Rab-GDP
A. Rab-GTP
Which stimulates
Rab-GTP to
hydrolyze its GTP
to GDP?
A. GAP
B. GEF
C. GDI
A. GAP (OFF)
A mitochondrion with
ubiquitin tags on
outer membrane
proteins is delivered
to the lysosome via:
A. Phagocytosis
B. Autophagy
C. Endocytosis
D. macropinocytosis
B. Autophagy
Why does secretion of
neurotransmitters
happen so rapidly upon a
local increase in [Ca2+]?
A. Neurotransmitters are
fast, fast, fast
B. That’s an action
potential, baby?
C. The SNARE-like
proteins are already
partially bundled
C. The SNARE-like
proteins are already
partially bundled
Which has an exit signal?
A. ER resident protein
B. Protein bound for a non-ER compartment in the endomembrane system
B. Protein bound for a non-ER compartment in the endomembrane system
Which has an ER retrieval sequence?
A. ER resident protein
B. Protein bound for a non-ER compartment in the
endomembrane system
A. ER resident protein
Vesicles forming to carry cargo from the ER to the Golgi bud toward:
A. The cytosol
B. the ER lumen
A. The cytosol
Which has a mannose-6 phosphate (M6P) tag?
A. Lyososomal hydrolase
B. ER resident protein
C. peroxisomal
protein
D. Mitochondrial protein
E. secreted protein
A. Lyososomal hydrolase
In a type of microscopy that relies on patterns of light and dark to visualize cells, parts of cells that appear darker are because:
A. Light waves are in phase
B. Light waves are out of phase
B. Light waves are out of phase
Interaction of light with an object produces phase changes
resulting in interference effects:
A) Edge appears as series of parallel lines
B) Point of light appears as concentric circles
Two objects close together might have overlapping images that
appear as one object.
B) Point of light appears as concentric circles
Two objects close together might have overlapping images that
appear as one object.
Which color of light has a longer
wavelength?
A. Red
B. violet
A. Red
Resolution is “better” when:
A) Two objects closer together can be seen as separate
B) Two objects need to be farther apart to be seen as separate
A) Two objects closer together can be seen as separate
How does wavelength affect resolution?
A) longer wavelength gives better resolution
B) shorter wavelength gives better resolution
B) shorter wavelength gives better resolution
Which gives better resolution:
A) ultraviolet
B) infrared
A) ultraviolet
Which of these is an approach to visualize cells with colored stains or markers?
A. Bright-feild
B. Dark-feild
C. Phase-contrast or DIC (highlights edges)
A. Bright-feild
Emission wavelength is _________ excitation wavelength.
A. longer than
B. shorter than
C. the same as
A. longer than
In situ hybridization would be a suitable approach to determine the location of:
A. A protein
B. A carbohydrate group
C. A lipid group
D. An RNA
D. An RNA
If a fluorophore is excited with yellow light, it will most likely
emit light in the ______ range.
A. Violet
B. Blue
C. Green
D. Red
D. Red
In a FRET pair, emission wavelength of the first in a pair is
_________ excitation wavelength of the FRET partner.
A. much longer than
B. much shorter than
C. about the same as
B. much shorter than
What would you use to determine whether two proteins
are co-localized?
A. FRET
B. FRAP
C. in situ hybridization
A. FRET
What would you use to determine whether a protein or
lipid diffuses freely around a membrane or can be replaced in a subcellular compartment?
A. FRET
B. FRAP
C. in situ hybridization
B. FRAP
What approach would you use to get better resolution without fancy microscopes or data processing?
A. Structured illumination microscopy
B. Expansion microcopy
C. Single molecule localization
D. Image deconvolution
E. Stimulated emission depletion
A. Structured illumination microscopy
The wavelength of an electron beam is ________ the wavelength of visible light.
A. Much shorter than
B. Much longer than
C. About the same as
A. Much shorter than
So, the resolution (distance at which two objects can be detected as separate) for electron microscopy is _______ than for light microscopy.
A. Much shorter than
B. Much longer than
C. About the same as
A. Much shorter than
We call the ability to resolve objects that are closer together:
A. Better or higher resolution
B. Worse or lower resolution
A. Better or higher resolution
Which would be useful for visualizing living cells?
A. Electron microscopy
B. light microscopy
B. light microscopy
