Txtbk questions Flashcards
Which of the following statements regarding vesicular transport is correct?
a. SNARE proteins transport water into the site of membrane fusion
b. Dynamin polymerization facilitates vessel fusion.
c. COPI-coated membranes are responsible for forming vesicles originating on the plasma membrane.
d. Clathrin-coated triskelions are composed of three heavy chains and three light chains
d
Kinases that phosphorylate phosphatidylinositol (PI) will NOT produce which of the following?
PI(4)P.
PI(3,5)P2
.PI(5)P.
PI(3)P.
b
An artificial membrane-bound container is filled with purified tubulin subunits, a purfied centrosome, purified Dynein complexes and the necessary small molecules for protein activities. Over time, where would the Dynein complexes accumulate?
Near the centre of the compartment
Near the outer membrane of the compartment
Homogenously throughout the compartment
On microtubules throughout the compartment
a
In a centrosome, which structures serve as nucleation sites for the formation of microtubules?
γ-tubulin rings
αβ-tubulin dimers
α- and β-tubulin monomers
Tubulin protofilaments
a
Microtubules and actin filaments share all of the following properties EXCEPT:
They associate with motor proteins.
Their subunits bind ATP, which is hydrolyzed after assembly.
They assemble and disassemble at their ends.
They are intrinsically polar structures.
b
How are the layers of the cerebral cortex formed?
a. The neurons are born at specific layers.
b.Neurons form axons that migrate on their own to specific layers.
c. Neurons form axons that migrate along glial cells to specific layers.
d. Entire neuronal cells migrate to specific layers.
D
You discover a frog mutant in which the nervous system abnormally forms on the surface of the embryo. Which of the following processes is most likely affected?
a. The constriction of actin filaments at the apical ends of epithelial cells
b. Endoderm development
c. An epithelial-to-mesenchymal transition
d. Single cell migration
A
Which of the following statements regarding tight junctions isNOTcorrect?
a. Mutations stopping the formation of tight junctions would stop the occlusion of molecules.
b. Tight junctions can form sealing strands between two cell membranes.
c. An extracellular tracer molecule added to the basolateral side of an epithelium cannot be transported between the cells to the apical side.
d. Tight junctions only interact heterotypically.
D
If extracellular calcium were removed, which of the following would occur?
a. Cadherin-actin binding would be inhibited.
b. Cadherin homotypic binding would be inhibited.
c. All contacts between epithelial cells would be removed.
d. Cadherins would bind each other, functioning like “Velcro” to hold cells together.
B
Which of the following statements regarding epithelial tissue isNOTcorrect?
a. Epithelial tissue in the small intestine may be connected via cadherins.
b. In epithelial tissue, links between cells via anchoring junctions can help resist stress.
c. In epithelial tissue, the extracellular matrix resists the majority of tension and compression.
d. In epithelial tissue, tight junctions occupy the most apical position, followed by adherens junctions, and desmosomes.
C
