The chemical basis for DNA replication involves the processes of unwinding the double helix, complementary base pairing, and synthesis of new strands. The enzyme DNA polymerase plays a crucial role in adding nucleotides to the growing DNA strand, using existing templates. Hydrogen bonds form between complementary bases (adenine with thymine, and cytosine with guanine) to ensure accurate replication. This precise process ensures genetic information is accurately copied and passed on during cell division, essential for growth and maintenance of organisms.