The flow of genetic information in biological systems from DNA>RNA>Protein is the central dogma in molecular biology. This explains how the genetic information in the form of DNA in a cell is converted to RNA and then to protein for effective utilization.
The process of replication allows cells to generate new genetic material (DNA) using original DNA as a template. The cell cycle consists of four phases-G1, S, G2, and M. During the G1 phase, cells grow and produce material like nucleotide precursors as preparation for DNA replication in the S-phase. Replication occurs in the S-phase cell and new genetic material is synthesized as a preparation for the cell division. Synthesis of histones and other DNA associated proteins is markedly increased in the S-phase. The process is highly regulated and requires many different enzymes that include DNA polymerase, primase, ligase, helicase, and topoisomerase. Replication is known to be semiconservative as the original DNA (the parent strand) splits to make a new strand, while retaining the parent strand.
Replication in prokaryotic and eukaryotic cells is quite similar. The difference in eukaryotic replication lies in the larger amount of DNA that is associated with histones. The prokaryotic DNA is circular and therefore has only one point of origin where replication starts and moves in a bidirectional manner. Eukaryotic cells, on the other hand, have a linear structure that is organized into tight chromosomes around histones.
Transcription is the process where a specific segment of DNA is used as a template and copied into an RNA molecule. This synthesis is carried out by an enzyme known as RNA polymerase. The newly synthesized RNA molecule then exits the nucleus and enters the cytoplasm, where it is translated into protein.
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