DNA polymerase synthesizes new DNA in which direction relative to the template strand?

DNA polymerase synthesizes new DNA in which direction relative to the template strand?

• A. 3' to 5'
• B. 5' to 3'
• C. 2' to 3'
• D. 4' to 5'

Answer: (B)

DNA polymerase can only extend a DNA chain at a free 3' end, so new DNA is synthesized in the 5' to 3' direction. While the enzyme reads the template strand in the 3' to 5' direction, adding nucleotides to the growing strand's 3' end results in a new strand that is built opposite the template (antiparallel). This 5' to 3' elongation is driven by the chemistry of nucleotide incorporation, which requires a free 3' hydroxyl group to form the next phosphodiester bond.

DNA polymerase can only extend a DNA chain at a free 3' end, so new DNA is synthesized in the 5' to 3' direction. While the enzyme reads the template strand in the 3' to 5' direction, adding nucleotides to the growing strand's 3' end results in a new strand that is built opposite the template (antiparallel). This 5' to 3' elongation is driven by the chemistry of nucleotide incorporation, which requires a free 3' hydroxyl group to form the next phosphodiester bond.