Question

Briefly explain why DNA replication is semiconservative and discontinuous. Make sure to name the proteins involved in the synthesis of DNA, synthesis of RNA, the removal of RNA and the sealing of the nicks.

Answer 1

Answer:

DNA replication is semiconservative: each new strand has a strand of the parent DNA and another strand of new synthesis. DNA synthesis is discontinuous, since one of the strands, the lagging strand, replicates intermittently within the replication bubble, while the leading strand replicates continuously. For replication, apart from DNA polymerases,  requires the action of enzymes that synthesize the primer, DNA ligases, enzymes that are responsible for joining pieces formed of chains, etc. RNA is synthesized through a process called transcription in making a complementary copy of a piece of DNA.

Explanation:

Replication is discontinuous since one of the strands, the lagging strand, replicates intermittently within the replication bubble, while the leading strand replicates continuously. It is bi-directional, because the strand is copied in both directions, and depending on the point of origin and the way it is viewed, a strand can be either discontinuous or continuous. Finally, replication is said to be semi-conservative since the original strands are part of each of the double strands resulting from replication.The unwinding of the DNA and the maintenance of the two separate strands in the replication fork so that the two new strands can be synthesized requires the action of proteins: Gyrase allows the release of the torque tension of the DNA double strand while the helicase separates the strands, allowing the action of DNA polymerases, which are responsible for the inclusion of new nucleotides as the DNA model strand is copied. Finally, the primases allow the incorporation of leader sequences at the beginning of the replication forks, allowing the action of DNA polymerases. DNA ligases seal cuts or nicks (broken phosphodiester bonds). DNA ligase also splices the ends of DNA into duplex regions. Transcription consists of the synthesis of RNA taking DNA as a template and means the passage of the information contained in DNA to RNA. The transfer of information from DNA to RNA is carried out following the complementary rules of the nitrogenous bases. When the entire strand has been copied, at the end of the process, the RNA chain is free and the DNA is closed again, by pairing of its complementary chains.