... are joined together to form the new DNA strand. Deoxribonucleotide triphosphates are first paired with their corresponding, complementary partner on the original, or template strand (blue in the above diagram). Adenine (A) is always paired with Thymine (T) and Guanine (G) with Cytosine (C).

A diphosphate is removed from the incoming nucleotide and a join made with the existing strand. In this way the growing, new DNA strand lengthens on nucleotide at a time until the strand is complete.