CH. 13: Lecture Question COMPLETE Flashcards
If a soluble protein from the
lumen of a donor compartment is
trafficked to a target compartment,
it will be in:
A. The target compartment lumen
B. The cytosol
C. The target compartment
membrane
A. The target compartment lumen
A transmembrane protein of a donor compartment is trafficked to a target compartment, where it is in:
A. The target compartment lumen
B. The cytosol
C. The target compartment
membrane
C. The target compartment
membrane
If part of a transmembrane
protein that faces the cytosol in
one compartment is trafficked
to a target compartment, there it
will face:
A. The target compartment lumen
B. The cytosol
C. The target compartment
membrane
B. The cytosol
How does assembly of a clathrin coat drive vesicle formation?
A. It utilizes ATP to assemble the membrane
B. It relies on motor proteins to initiate vesicle formation
C. It promotes membrane curvature
C. It promotes membrane curvature
In this figure, the adaptin DOES NOT bind:
A. Cargo
B. Cargo receptor
C. Clathrin triskelion
A. Cargo
What do you suppose that little
yellow dynamin protein does?
A. Recruits cargo
B. Binds cargo receptors
C. Recruits the clathrin coat
D. Pinches off the vesicle
from the donor membrane!
D. Pinches off the vesicle
from the donor membrane!
How many different singly-
phosphorylated PI forms are
there?
A) 1
B) 2
C) 3
C) 3
How many doubly-
phosphorylated forms are there?
A) 1
B) 2
C) 3
C) 3
How many triply-
phosphorylated forms are there?
A) 1
B) 2
C) 3
A) 1
Different phosphoinositide species recruit only proteins with specific phosphoinositide binding domains.
True or False
True
Kinase:
transfers a
phosphate group from a
donor to a target (usually
from ATP to –OH group).
Phosphatase hydrolyzes a
phosphoester bond to
remove a phosphate group
What stimulates Sar1 to release GDP and bind GTP?
A. A Sar1 GAP (GTPase-activating protein)
B. A Sar1 GDI (GDP dissociation inhibitor)
C. A Sar1 GEF (guanine nucleotide exchange factor)
C. A Sar1 GEF (guanine nucleotide exchange factor)
An amphipathic helix juts out and can anchor in the cytosolic leaflet
of a membrane when Sar1 is bound to:
A. GDP
B. GTP
B. GTP
What hydrolyzes GTP to GDP on Sar1?
A. The native GTPase activity of Sar1
B. A Sar1 GDI (GDP dissociation inhibitor)
C. A Sar1 GEF (guanine nucleotide exchange factor)
D. A Sar1 GAP
D. A Sar1 GAP
What would remove a phosphate group from PI(3)P?
A. A phosphatidylinositol 3-kinase (PI3K)
B. A phosphatidylinositol 3-phosphatase
B. A phosphatidylinositol 3-phosphatase
What stimulates the GTPase activity of a Rab?
A. A Rab GAP
B. A Rab GEF
A. A Rab GAP
KDEL receptors bind proteins with KDEL sequences when pH is lower
than the pH of the ER lumen. What causes the lower pHs of compartments from which proteins with KDEL sequences are
retrieved?
A. An ATP-dependent proton pump that moves protons from the cytosol to the compartment lumen
B. An ATP-dependent proton pump that moves protons from the
compartment lumen to the cytosol
C. Facilitated diffusion of protons down an electrochemical gradient
A. An ATP-dependent proton pump that moves protons from the cytosol to the compartment lumen
What happens if a protein’s KDEL sequence is blocked by a drug?
A. The protein won’t bind KDEL receptors
B. The protein won’t be retrieved to the ER
C. The protein will likely be secreted, though slowly, because
aggregation of ER resident proteins is another mechanism for
retention
D. All of the above
D. All of the above
The M6P receptor
* Binds at pH 6.5-6.7 in
the trans-Golgi
network
* Releases at pH 6.0 or
lower (e.g. at the
endosome)
True or False
True
Generally, vesicle coats promote budding of vesicles toward:
A. The cytosol
B. The lumen of a
compartment or
extracellular space
A. The cytosol
If a multivesicular
body were to fuse with the
plasma membrane, where
would the vesicles be?
A. The cytosol
B. The lumen of a
compartment or
extracellular space
B. The lumen of a
compartment or
extracellular space
LDL receptors bind LDL particles at:
A. Slightly basic pH
B. Somewhat acidic pH
A. Slightly basic pH
LDL receptors release LDL particles at:
A. Slightly basic pH
B. Somewhat acidic pH
B. Somewhat acidic pH
How does an antibody in a mother’s milk make its way from an infant’s gut to the fluid near capillaries?
A. By degradation in
the lysosome
B. Transcytosis
C. Facilitated diffusion
D. Insertion into the ER
B. Transcytosis
What’s a likely
mechanism for catch
and release?
A. Differences in pH
B. The protein knows
where it’s going
A. Differences in pH
Why does insulin stimulate glucose uptake in tissues such as skeletal
muscle, heart, and adipose tissue?
A. It causes more cell-surface localization of glucose carrier
proteins (glucose transporters)
B. It increases simple diffusion
C. it carries glucose into the cell
D. the insulin receptor is endocytosed along with glucose
A. It causes more cell-surface localization of glucose carrier
proteins (glucose transporters)
Which way to ESCRT protein complexes bend a membrane?
A. Toward the cytosol
B. Toward the non-cytosolic side
A. Toward the cytosol
Would acid hydrolases function
in the cytosol or in the
extracellular fluid (pH ~ 7.4)?
A. yep!
B. Probably not so much
B. Probably not so much
Acid hydrolases of the late
lysosome, the lysosome,
and the endolysome:
A. Had a specific tag that
delivered them to the
three different locations
B. All were delivered by
vesicles after capture by
an M6P receptor
B. All were delivered by
vesicles after capture by
an M6P receptor (equivalent compartments)
Phosphoinositides stimulate actin polymerization and then closure of
the phagosome and reorganization of the base
True or False
True
When would you expect autophagy to be increased?
A. When nutrients are scarce
B. when nutrients are plentiful
A. When nutrients are scarce
