Practice question

E. coli possesses five DNA polymerases, but bulk chromosome duplication is performed exclusively by DNA polymerase III holoenzyme. Pol III exists as dimeric asymmetric complex containing alpha polymerase, epsilon proofreading exonuclease, theta stabilizer, tau dimerization, beta sliding clamp, and gamma clamp loader plus chi psi subunits. Its very high processivity exceeding 500 kilobases and rapid rate near 750 nucleotides per second allows simultaneous leading and lagging strand synthesis within replisome. Pol I mainly fills gaps and removes primers while Pol II, IV, V function primarily in repair.