The attachment of nucleotides during DNA replication is critically dependent on the hydroxyl group. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The sugar in the nucleotide, specifically deoxyribose in DNA, has a hydroxyl group (-OH) attached to the 3' carbon atom.
During replication, the enzyme DNA polymerase catalyzes the addition of nucleotides to the growing DNA strand. This process involves the formation of phosphodiester bonds between the hydroxyl group of the existing nucleotide chain and the phosphate group of the incoming nucleotide. The hydroxyl group's reactivity is essential as it provides the necessary site for this bond formation, thus extending the DNA strand.
Therefore, the hydroxyl group plays a vital role during DNA replication, facilitating the successive addition of nucleotides to ensure the accurate synthesis of new DNA strands. This understanding emphasizes the importance of functional groups in biochemical processes, particularly in molecular biology.