Which enzyme is responsible for adding nucleotides to a growing DNA strand during replication?

DNA polymerase is the enzyme responsible for adding nucleotides to a growing DNA strand during replication. Its main function is to synthesize new DNA strands complementary to the template strand. During DNA replication, DNA polymerase reads the existing DNA strand and incorporates the correct nucleotides (adenine, thymine, cytosine, and guanine) to build a new strand, ensuring accurate replication of genetic information.

This process is fundamental for the duplication of DNA prior to cellular division and is critical for maintaining the integrity of genetic material across generations. DNA polymerase also has proofreading capabilities, which allow it to correct errors that might occur during replication, further contributing to the fidelity of the genetic code.

In contrast, other enzymes mentioned serve different functions in DNA replication. RNA polymerase synthesizes RNA, not DNA; helicase unwinds the double-stranded DNA, allowing the strands to separate; and DNA ligase is responsible for connecting and sealing gaps between DNA fragments, particularly on the lagging strand during replication. Each of these enzymes plays an essential role, but it is DNA polymerase that specifically adds nucleotides to form the new DNA strand.