DnaA is provided by its response to phospholipids. Phospholipids promote the exchange of ATP with ADP bound to DnaA.

TLS Online TPP Program

#Id: 8321

#Unit 2. Cellular Organization

Elongation phase

short oligomer rapidly increases in length by the addition of actin monomers to both of its ends, causing filament elongation

TLS Online TPP Program

#Id: 8322

#Unit 2. Cellular Organization

Steady-state phase

G-actin monomers exchange with subunits at the filament ends, but there is no net change in the total length of filaments.

TLS Online TPP Program

#Id: 8323

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 8324

#Unit 2. Cellular Organization

The rate of addition of monomers is given by

rate constant kon (M–1 sec–1 )

The rate of loss is given by koff (sec–1)

TLS Online TPP Program

#Id: 8325

#Unit 2. Cellular Organization

Critical concentration (Cc)

minimal concentration of monomers at which filaments form

TLS Online TPP Program

#Id: 8326

#Unit 2. Cellular Organization

The two ends of microfilament polymerize at different rates:

fast-growing end - plus end

slow-growing end - minus end