Final answer:
The energy for transcription comes from the hydrolysis of nucleotide triphosphates, mainly ATP, which is regenerated through the metabolism of glucose. An AT-rich region such as the TATA box facilitates the initiation of transcription by requiring less energy to separate the DNA strands.
Step-by-step explanation:
The energy that drives transcription comes from the hydrolysis of nucleotide triphosphates (NTPs), which are integrated into the growing RNA strand. Breaking the high-energy bonds of these NTPs releases the energy needed for the transcription process. Specifically, adenosine triphosphate (ATP) is the molecule that provides the energy for transcription, as well as other cellular processes. ATP is regenerated through the metabolism of sugars like glucose in cellular respiration, linking energy-releasing pathways (exergonic pathways) to energy-requiring pathways (endergonic pathways) in the cell.
An AT-rich region in the DNA sequence where transcription is initiated, known as the TATA box, serves as the recognition site for transcription factors. This region is advantageous because A-T pairs have two hydrogen bonds compared to the three in G-C pairs, making the region easier to unwind. This lower energy requirement for DNA strand separation facilitates the initiation of transcription by the RNA polymerase enzyme.