همانندسازی DNA скачать в хорошем качестве

همانندسازی DNA

این ویدیو شامل تمام جزئیات و آنزیم‌های دخیل در فرآیند همانندسازی DNA در یوکایوتها و پروکاریوتها می‌باشد -Replication begins at a sequence called an origin -At a replication fork, one daughter strand (the leading strand) is elongated continuously. The other daughter strand (the lagging strand) is formed as a series of discontinuous Okazaki fragments from primers synthesized every 100 to 200 nucleotides The ribonucleotides at the 5′ end of each Okazaki fragment are removed and replaced by elongation of the 3′ end of the next Okazaki fragment. Finally, adjacent Okazaki fragments are joined by DNA ligase Most of the DNA in eukaryotic cells is synthesized by Pol δ and Pol ε, which take over from Pol α and continue elongation of the daughter strands in the 5′→3′ direction. Pol δ synthesizes most of the length of the lagging strand, while Pol ε synthesizes the leading strand. Pol δ and Pol ε remain stably associated with the template by binding to PCNA, a trimeric protein that encircles the daughter duplex DNA, functioning as a sliding clamp