5' Vs 3' Ends of DNA

• DNA polymerases have proofreading ability - they can detect if there has been a mistake during replication and remove the incorrect base from the growing chain by breaking the bond with the sugar-phosphate backbone.
• The active site of DNA polymerase contains amino acids which are complementary to the bases on the template strand, allowing it to bind to them.
• Primers are short RNA molecules synthesised on the template strand by an enzyme called primase
• Amino acid residues at the active site of DNA polymerase form hydrogen bonds with the bases on the template strand
• Hydrogen bonds between the amino acid residues and the bases on the template strand stabilise the binding of the enzyme to the template strand
• RNA primers act as starting points for DNA polymerase III holoenzyme to begin copying the DNA sequence