Final answer:
DNA polymerases add nucleotides to the 3'-OH end of the growing DNA strand and not onto the 5' phosphate, creating new DNA in the 5' to 3' direction. The statement in the question is false.
Step-by-step explanation:
The statement that DNA polymerases always synthesize new DNA by adding nucleotides onto the 5' phosphate is false. DNA polymerases actually add nucleotides to the free 3'-OH group present on the growing DNA strand, forming a phosphodiester bond between the 3'-OH end of the new nucleotide and the 5' phosphate group of the last nucleotide of the growing chain. Therefore, DNA polymerases synthesize new DNA in the 5' to 3' direction, and this synthesis requires a free 3'-OH group to proceed. Correct synthesis involves reading the template strand in the 3' to 5' direction while adding new nucleotides in the 5' to 3' direction.
The leading strand is synthesized continuously towards the replication fork. In contrast, the lagging strand is synthesized in the opposite direction in the form of Okazaki fragments, which also grow in the 5' to 3' direction but require multiple primers to initiate synthesis at intervals. These fragments are later joined to form a continuous strand.