Final answer:
Enzymes used in DNA replication and transcription are specialized proteins, such as DNA polymerase, which add nucleotides to a growing DNA strand by catalyzing the necessary chemical reactions.
Step-by-step explanation:
The enzymes used in DNA replication and transcription are part of a larger class of molecules known as proteins. Enzymes such as DNA polymerase play a critical role in adding nucleotides to the growing DNA chain during DNA replication. These enzymes are highly specialized proteins that catalyze the various reactions necessary for the replication and transcription processes. In both prokaryotes and eukaryotes, multiple types of DNA polymerases exist, with DNA pol I, DNA pol II, and DNA pol III being notable examples in prokaryotes, and DNA polymerase alpha, delta, and epsilon playing significant roles in eukaryotic replication. The energy for the addition of nucleotides is derived from the nucleotides themselves, which come with three phosphate groups attached, providing the necessary power to form the essential phosphodiester bonds in the growing DNA strand.