Final answer:
The unwinding and stabilization of newly opened DNA during replication are supported by enzymes such as helicase and topoisomerases, with helicase unwinding DNA and topoisomerases relieving supercoiling stress. Single-stranded DNA-binding proteins stabilize the open strands, and DNA polymerase, with the help of primase and PCNA, adds new nucleotides, with DNA ligase later joining fragments and sealing nicks.
Step-by-step explanation:
During DNA replication, the stability and unwinding of the newly opened DNA are facilitated by a series of specialized proteins and enzymes. An enzyme called helicase is responsible for separating the DNA strands by breaking the hydrogen bonds between the nitrogenous base pairs, which requires energy in the form of ATP hydrolysis. Once the DNA is open, single-stranded DNA-binding proteins, or SSBs, coat the single-stranded DNA near the replication fork to prevent rewinding. Additionally, topoisomerases, particularly DNA gyrase in bacteria, play a crucial role in relaxing the supercoiled chromosome, making DNA more accessible for replication, and relieving stress on the DNA during unwinding by causing breaks and resealing the DNA.
Further in the process, an enzyme known as primase synthesizes a short RNA primer, providing a starting point for DNA synthesis. DNA polymerase then adds nucleotides to the primer, growing the new strand in the 5' to 3' direction. The Proliferating Cell Nuclear Antigen (PCNA), a sliding clamp protein, holds DNA polymerase in place during this process. Following the removal of RNA primers, DNA ligase seals the nicks to complete the replication of DNA strands.