Final answer:
It is true that DNA replication begins with an RNA primer. Primase synthesizes the RNA primer necessary for DNA polymerase to add DNA nucleotides and carry out strand elongation.
Step-by-step explanation:
The statement that DNA strand replication begins with an RNA primer is true. During the process of DNA replication, enzymes such as helicase first open the DNA at the origin of replication, forming a replication fork. An enzyme called primase then synthesizes an RNA primer, which is a short stretch of RNA nucleotides. This RNA primer is necessary because DNA polymerase, the enzyme responsible for adding DNA nucleotides, can only add to an existing strand of nucleotides; it cannot initiate the synthesis of a new strand on its own. Therefore, the RNA primer provides a starting point for DNA polymerase to begin adding DNA nucleotides.
On the leading strand, DNA is synthesized continuously in the direction of the replication fork. Conversely, on the lagging strand, synthesis occurs away from the replication fork in short segments known as Okazaki fragments. Each of these fragments begins with an RNA primer. After the replication process, the RNA primers are removed and replaced with DNA nucleotides, and the nicks between the newly synthesized DNA fragments are sealed by DNA ligase, completing the replication process.