Question

DNA synthesis is the joining of _______? Nucleotides can only be added from what end? Therefore DNA synthesis occurs in what direction? What provides the energy for the formation of each new phosphodiester bond?

Answer 1

DNA synthesis is the process by which nucleotides are joined in a 5' to 3' direction, adding to the 3' end of the growing strand. This process is energetically driven by the hydrolysis of pyrophosphate from nucleotide triphosphates.

Step-by-step explanation:

During DNA synthesis, nucleotides are joined together to form a new DNA strand. Nucleotides can only be added from the 3' end of the growing DNA strand, thus DNA synthesis occurs in a 5' to 3' direction. The energy necessary for the formation of each new phosphodiester bond comes from the breakdown of the nucleotide triphosphates (dNTPs) that are used as substrates. Specifically, when a nucleotide is incorporated into the growing DNA chain, the two outermost phosphate groups are released as pyrophosphate, and this pyrophosphate is subsequently hydrolyzed in an energetically favorable reaction that drives the polymerization process.