Why is DNA replication described as semi-conservative?

DNA replication is described as semi-conservative because, in this process, each newly synthesized DNA molecule is composed of one original (parental) strand and one newly formed strand. This means that when DNA replicates, it does so in a way that conserves half of the parental DNA material in each of the daughter molecules.

This characteristic is crucial as it ensures that genetic information is accurately passed from one generation to the next. The structure of DNA, which includes complementary base pairing, allows each strand to serve as a template for the new strand during replication. Therefore, after the replication process, each of the two resulting double helices contains one strand that is identical to the original and one that is newly synthesized.

In contrast, the other options do not accurately reflect the fundamental nature of DNA replication. For example, stating that each new DNA molecule contains two new strands does not align with the semi-conservative nature of replication, wherein one strand is always old and the other new. Saying that replication occurs more than once in each cycle misrepresents the process, as DNA replication occurs once during the cell cycle before cell division. Finally, the notion that only half of the DNA is replicated at each stage does not capture the complete picture, as replication involves