Final answer:
Energy for the polymerization of RNA from a DNA template during transcription is released from the hydrolysis of pyrophosphate as NTPs are incorporated into the RNA strand by RNA polymerase.
Step-by-step explanation:
The energy that drives the polymerization of RNA from a DNA template is provided by the hydrolysis of pyrophosphate (PP) into two inorganic phosphates. This reaction occurs when a nucleoside triphosphate (NTP) is added to the growing RNA chain. As the two phosphates break off the incoming NTP, energy is released, and this energy is used to form a new phosphodiester bond with the RNA molecule. RNA polymerase is the enzyme responsible for this process, moving along the DNA template strand in the 3' to 5' direction, while synthesizing RNA in the 5' to 3' direction. Each of the four RNA nucleotides (ATP, UTP, CTP, GTP) is paired with its complementary DNA base, facilitated by the Mg²⁺ ion, which is required for the catalytic activity of the RNA polymerase.