Final answer:
During DNA replication, a dNTP converts into a deoxynucleotide and releases two phosphates as pyrophosphate upon addition to a growing DNA strand by an enzyme called DNA polymerase. Dideoxynucleotides, used in DNA sequencing, terminate the synthesis since they lack the 3' hydroxyl group needed for further elongation.
Step-by-step explanation:
When a new base is added to a growing DNA strand, dNTP (deoxynucleotide triphosphate) converts to a deoxynucleotide while releasing two additional phosphates as pyrophosphate. This process occurs during the elongation stage of DNA replication, where DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base.
In contrast, dideoxynucleotides (ddNTPs) lack the critical 3' hydroxyl group, which is necessary for forming the next phosphodiester bond in the growing DNA chain. Thus, when a ddNTP is incorporated into a DNA strand, it results in the termination of the DNA synthesis because no further nucleotides can be added. This property of ddNTPs is the foundation of the Sanger method for DNA sequencing, where they are used to generate DNA fragments of varying lengths that can be used to determine the DNA sequence through electrophoresis.