Final answer:
The key enzyme for the DNA synthesis step in Sanger/dideoxy sequencing is DNA polymerase.
Step-by-step explanation:
The pivotal enzyme in the Sanger/dideoxy sequencing method's DNA synthesis step is DNA polymerase. DNA polymerase plays a crucial role in extending the DNA chain by adding nucleotides.
In the Sanger sequencing approach, it integrates dideoxynucleotides alongside regular nucleotides.
These dideoxynucleotides lack a 3'-OH group, causing chain termination at specific points. This process results in a set of DNA fragments of varying lengths, each terminating at a specific nucleotide position.
Through gel electrophoresis, these fragments are separated based on size, enabling the determination of the DNA sequence by identifying the terminal nucleotides. The controlled termination at specific points facilitates accurate sequencing.