DNA strand elongation

(a) Complementary nucleotides form hydrogen bonds by the attraction of positive and negative charges. The nucleotide triphosphate complementary to the template strand nucleotide is recruited by DNA polymerase. (b) DNA polymerase catalyzes the addition of the new nucleotide to the 3 end of the growing strand by removing two phosphates (the pyrophosphate group) and forming a new phosphodiester bond(a) Complementary nucleotides form hydrogen bonds by the attraction of positive and negative charges. The nucleotide triphosphate complementary to the template strand nucleotide is recruited by DNA polymerase. (b) DNA polymerase catalyzes the addition of the new nucleotide to the 3 end of the growing strand by removing two phosphates (the pyrophosphate group) and forming a new phosphodiester bond

(a) New strand Template strand [—E l—% 5' 3‘ Hydrogen bond V Phosphodiester Deoxyadenosine In a reaction catalyzed by DNA polymerase, and using thymine on the template strand (right) as a guide,theactivated3‘OHofthedeoxycytidinein the growing strand (left) attad<s the triphosphate group of the incoming dATP. (b) New strand Template strand New Sugar-phosphate phosphodiester backbone bond phosphodiester bond attaching adenosine DNA polymerase catalyzes formation of a new monophosphate to the 3’ end of the new strand. Pyrophosphate 9r°Up (discarded) 5.