DNA Polymerases: Building the Foundation of Life

How do DNA polymerases extend the primer?

A. the 3'OH of the primer

B. the 5' phosphate of the primer

C. the promoter site

D. the complementary strand

Answer:

DNA polymerases extend the primer by joining deoxynucleotides with the 3'OH of the primer. Therefore, the correct option is A.

DNA polymerases play a crucial role in the process of DNA replication. They are enzymes responsible for synthesizing new DNA strands by adding nucleotides to the growing chain. One of the key steps in DNA replication is the extension of the primer by DNA polymerases.

The primer, usually a short strand of RNA, provides the starting point for DNA synthesis. DNA polymerases recognize the primer and begin adding complementary deoxynucleotides to it. In this process, DNA polymerases form phosphodiester bonds between the 3' hydroxyl group (3'OH) of the primer and the incoming deoxynucleotides.

By joining deoxynucleotides with the 3'OH of the primer, DNA polymerases create a complementary strand of DNA that matches the template strand. This accurate and efficient process is essential for maintaining the integrity of genetic information during cell division and growth.

Understanding the role of DNA polymerases in DNA replication provides insights into the fundamental mechanisms of genetic inheritance and molecular biology. By studying how these enzymes work, researchers can uncover new discoveries and innovations in fields such as biotechnology, medicine, and genetics.