Lecture 13 Flashcards
Define Microfilaments
Smallest of the cytoskeletal filaments
What are microfilaments involved in?
cell migration
amoeboid movement
cytoplasmic streaming
Define actin
Very abundant protein in all eukaryotic cells
Once synthesized actin
folds into globular shaped molecule that can bind atp or adp (G-actin)
G actin molecules polymerize to form
microfilaments, f-actin
Actins can be divided into
muscle-specific (alpha actins)
nonmuscle (beta actins)
____ filaments are composed of two linear strands of polymerized G-actin wound into a helix
F-actin
True or false: all actin monomers in a filament have the same orientation
true
What type of monomers polymerize reversibly similar to tubulin assembly and how?
G-actin monomers
Lag phase and elongation phase
Describe the plus end of a microfilament
barbed end
Describe the minus end of a microfilament
Pointed end
Polarity of microfilaments is reflected in more rapid addition or loss of
G-actin at the plus end than the minus end
Growing microfilaments have ends that have
ATP actin
Most of a microfilament is composed of
ADP actin
After G-actin monomers assemble onto a microfilament
ATP bound to them is slowly hydrolyzed