Nucleic acid synthesis refers to the process of creating DNA and RNA molecules, which are essential for storing and transmitting genetic information in living organisms. This process occurs naturally in cells during replication and transcription, where enzymes like DNA polymerase and RNA polymerase play crucial roles in assembling nucleotide sequences. In laboratory settings, nucleic acid synthesis can also be performed artificially through techniques such as solid-phase synthesis or PCR (polymerase chain reaction). These methods allow scientists to produce specific sequences of nucleotides, enabling research in genetics, biotechnology, and medicine.