Final answer:
The specific site on the chromosome where DNA replication begins, and where proteins assemble for this process, is called the origin of replication. This site is a nucleotide sequence recognized by certain proteins, and the unwinding of DNA there is facilitated by the enzyme helicase.
Step-by-step explanation:
The name of the site on the chromosome where proteins involved in the initiation of DNA replication assemble is known as the origin of replication. In E. coli, a prokaryote, the origin is recognized by certain proteins which bind to this specific nucleotide sequence that is rich in adenine-thymine (AT) sequences. The enzyme helicase then unwinds the DNA at this point, separating the strands by breaking the hydrogen bonds between nitrogenous base pairs, thus allowing replication forks to form. These replication forks extend bidirectionally as replication proceeds, and the whole process is facilitated by ATP hydrolysis and aided by single-strand binding proteins and topoisomerases like DNA gyrase which relaxes the supercoiled chromosome.