Understanding DNA Replication

DNA replication is a biological process by which a cell duplicates its DNA molecule before it divides. This ensures that each new cell receives an exact copy of the genetic material.

Replication begins at specific locations called origins, where the double helix unwinds to form a 'Y' shaped replication fork. These forks are the actual sites where DNA replication occurs.

Helicase unwinds the DNA double helix, separating the two strands. This enzyme moves at an impressive speed, equivalent to spinning a DNA strand at 10,000 rpm.

Primase synthesizes a short RNA primer that provides a starting point for DNA polymerase to begin synthesis, as it can only add nucleotides to an existing strand.

DNA polymerase not only synthesizes new DNA strands but also proofreads each new nucleotide against its template. This ensures an incredibly low error rate, about one mistake per billion bases.

DNA is replicated simultaneously but asymmetrically. The leading strand is synthesized continuously, while the lagging strand is formed in short segments called Okazaki fragments.

Telomeres protect chromosome ends but shorten with each cell division. Telomerase replenishes telomeres, potentially impacting aging and cancer. Interestingly, lobsters express telomerase constantly, contributing to their long lifespan.