Final answer:
The discovery of Okazaki fragments revealed that DNA replication is semi-discontinuous, with bidirectional synthesis where the leading strand is made continuously and the lagging strand is made in fragments away from the replication fork.
Step-by-step explanation:
The discovery of Okazaki fragments indicated that DNA replication is semi-discontinuous and supports the concept that DNA replication in cells is bidirectional. During replication, one strand, known as the leading strand, is synthesized continuously towards the replication fork by DNA polymerase as it can add nucleotides only in the 5' to 3' direction, which matches the 3' to 5' orientation of the template strand.
The other strand, named the lagging strand, is synthesized away from the replication fork in Okazaki fragments, short sequences of DNA. These fragments later require RNA primers for the start of synthesis and are subsequently joined by DNA ligase. This semi-discontinuous process results from the antiparallel nature of DNA strands and the unidirectional activity of DNA polymerase.