Flashcards in Cytoskeleton (Sept. 5-Denning) Deck (44):
List the 3 types of main elements which compose the cytoskeleton
What is another name for Actin?
List the main functions of actin (microfilaments)
Cell Shape (surface area)
Actin can also allow for cell migration. What are the functions it facilitates.
Describe 3 general features of the structure of actin when monomers assemble into protogilaments
Monomers bind head to tail for form Plus (+) and Minus (-) end of chain
Binding site for ATP/ADP in the center
Aggregate into 2 chains of protofilaments
What happens when the ATP undergoes hydrolysis to ADP when actin filaments are coalesced together?
Gives rise to the instability of the actin filaments
What is the "ant-trail" analogy?
If a cell needs to move or respond to a signal it can rapidly depolymerize the actin on one side and reassemble the actin filaments on another side
The kinetics of actin filament formation:
(A) is spontaneous
(B) involve a nucleation lag phase followed by a rapid elongation phase and steady-state phase (equilibrium phase)
(C) depends on the final critical concentration
(D) Relies on the number of free actin subunits available
A - nucleation lag phase
B - there is a significant energy barrier that is present in the nucleation phase that must be overcome. Actin monomers aggregate into oligomers and then rapidly polymerize.
C - steady state is the final concentration of dynamic actin filaments and does not affect kinetics
D - # of free actin subunits affects final crit. concentrations. # of Nuclei and their addition affects elongation speed.