DNA polymerase is an essential enzyme involved in the process of DNA replication and repair. Its primary role is to synthesize a new DNA strand by adding nucleotides complementary to the template strand, ensuring the accurate replication of genetic information. DNA polymerase also plays a crucial role in DNA repair mechanisms, such as base excision repair and nucleotide excision repair, by filling in the gaps created during the repair process.During DNA replication, DNA polymerase reads the template strand in the 3' to 5' direction and synthesizes the new complementary strand in the 5' to 3' direction. It adds deoxyribonucleotide triphosphates dNTPs to the growing DNA strand, which are complementary to the template strand. For example, if the template strand has an adenine A base, DNA polymerase will add a thymine T to the new strand, and vice versa. Similarly, if the template strand has a cytosine C base, DNA polymerase will add a guanine G to the new strand, and vice versa.To ensure the accuracy of the newly synthesized DNA strand, DNA polymerase has a proofreading activity. This proofreading function is facilitated by the 3' to 5' exonuclease activity of the enzyme. If an incorrect nucleotide is added to the growing DNA strand, the enzyme detects the mismatch and removes the incorrect nucleotide using its exonuclease activity. After the removal of the incorrect nucleotide, DNA polymerase resumes the synthesis of the new strand by adding the correct complementary nucleotide.This proofreading activity significantly increases the fidelity of DNA replication, reducing the error rate from approximately one mistake per 10^5 nucleotides to about one mistake per 10^7 nucleotides. However, it is important to note that DNA polymerase is not infallible, and some errors may still occur during replication. These errors, if not corrected by other DNA repair mechanisms, can lead to mutations and potentially contribute to various genetic disorders or the development of cancer.In summary, DNA polymerase plays a critical role in DNA replication and repair by synthesizing new DNA strands and ensuring their accuracy through its proofreading activity. This helps maintain the integrity of the genetic information and prevents the accumulation of mutations in the genome.