The process of DNA replication is affected by an enzyme known as

The correct option is Polymerase I.

DNA replication is a highly coordinated biological process where a double-stranded DNA molecule is copied to produce two identical DNA molecules. This process requires a variety of specialized enzymes, each performing a specific role. Let us break down why Polymerase I is the correct enzyme among the choices provided:

1. Role of DNA Polymerase I: During DNA replication, replication on the lagging strand occurs discontinuously in short stretches called Okazaki fragments. Each of these fragments begins with a short RNA primer. DNA Polymerase I plays a critical role in maturation of these fragments. It possesses a unique 5' to 3' exonuclease activity that allows it to remove the RNA primers ahead of it. Simultaneously, its 5' to 3' polymerase activity synthesizes DNA to fill the resulting gaps with corresponding deoxyribonucleotides.

2. Analyzing the other options:
- Mutase: This is an enzyme of the isomerase class that catalyzes the movement of a functional group from one position to another within a single molecule (commonly seen in glycolysis, e.g., phosphoglycerate mutase). It is not a primary enzyme in the DNA replication machinery.
- Ligase: While DNA ligase is involved in DNA replication (it seals the nicks in the sugar-phosphate backbone by joining Okazaki fragments), the synthesis and gap-filling replication process itself is directly driven by polymerases. Among the direct choices for replicating/filling DNA synthesis, Polymerase I is the key polymerizing enzyme listed.
- Ribonuclease: While ribonucleases degrade RNA molecules, the specific enzyme responsible for the coordinated removal of RNA primers and replacement with DNA during replication is the multifunctional DNA Polymerase I.

Thus, the process of DNA replication is directly affected and carried out by the synthesis activity of Polymerase I.