Kornberg showed that nucleotides are added to the 3' end of each growing DNA strand. In what way does an exposed 3'-OH group participate in strand elongation?

Key Concepts

DNA Strand Elongation

DNA strand elongation is the process by which nucleotides are sequentially added to a growing DNA strand during DNA replication. This process occurs in the 5' to 3' direction, meaning that nucleotides are added to the 3' end of the existing strand. The enzyme DNA polymerase catalyzes this reaction, facilitating the formation of phosphodiester bonds between nucleotides.

3'-OH Group

The 3'-OH group is a hydroxyl functional group located at the 3' carbon of the sugar molecule in a nucleotide. This group is crucial for DNA synthesis because it serves as the attachment point for the incoming nucleotide's phosphate group. The presence of the 3'-OH group allows for the formation of a covalent bond, enabling the elongation of the DNA strand.

Phosphodiester Bond Formation

Phosphodiester bonds are the covalent linkages that connect nucleotides in a DNA strand. During DNA replication, the 3'-OH group of the last nucleotide in the growing strand reacts with the phosphate group of an incoming nucleotide, resulting in the release of a pyrophosphate molecule and the formation of a new phosphodiester bond. This reaction is essential for the continuous elongation of the DNA strand.