https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/replication/v/leading-and-lagging-strands-in-dna-replication 2023-12-04T19:02:25.924542584Z Leading and lagging strands in DNA replication DNA replication is a precise process where DNA unwinds and splits into two strands. Each strand then serves as a template for a new DNA molecule. The leading strand is built continuously, while the lagging strand is built in fragments, called Okazaki fragments. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/4246e827-19f5-4ce4-92e8-8cb36b5638a8_1280_720_base.png Leading and lagging strands in DNA replication DNA replication is a precise process where DNA unwinds and splits into two strands. Each strand then serves as a template for a new DNA molecule. The leading strand is built continuously, while the lagging strand is built in fragments, called Okazaki fragments. https://cdn.kastatic.org/ka-youtube-converted/eM7arWJJ3zk.mp4/eM7arWJJ3zk.mp4 619 Mechanism of DNA replication https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/replication/e/replication 2025-11-24T21:00:40.80360556Z Replication Test your knowledge of replication! Megan Cohn exercise https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:gene-expression-and-regulation/x230b3ff252126bb6:dna-structure-and-replication/a/dna-replication 2026-03-26T05:30:45.387289448Z DNA replication Learn about the enzymes and processes involved in copying DNA. article https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-replication/a/telomeres-telomerase 2025-06-30T13:17:39.587845569Z Telomeres and telomerase Telomeres as protective "caps" on the tips of eukaryotic chromosomes. How telomerase extends telomeres. article https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/replication/v/speed-and-precision-of-dna-replication 2023-06-22T09:32:02.370557018Z Speed and precision of DNA replication DNA replication is a complex, fast, and precise process involving enzymes like topoisomerase, helicase, and polymerase. In E. coli, polymerase can replicate up to 700+ base pairs per second. Initially, one mistake occurs for every 10 million nucleotides, but proofreading reduces errors to one in a billion. This amazing cellular machinery keeps our DNA accurate and functional. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/9b526092-5e87-40f7-8a89-f19bbba2fd74_1280_720_base.png Speed and precision of DNA replication DNA replication is a complex, fast, and precise process involving enzymes like topoisomerase, helicase, and polymerase. In E. coli, polymerase can replicate up to 700+ base pairs per second. Initially, one mistake occurs for every 10 million nucleotides, but proofreading reduces errors to one in a billion. This amazing cellular machinery keeps our DNA accurate and functional. https://cdn.kastatic.org/ka-youtube-converted/PSl6IXUCNuw.mp4/PSl6IXUCNuw.mp4 235 Mechanism of DNA replication https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/replication/a/hs-dna-structure-and-replication-review 2021-04-29T07:52:23Z DNA structure and replication review article https://www.khanacademy.org/science/grade-12-biology-snc-aligned/xa8ba3a087f1f5288:reproduction-and-inheritance/xa8ba3a087f1f5288:mechanism-of-dna-replication/v/dna-repair-1 2023-08-14T21:12:46.061619254Z DNA repair 1 DNA polymerase III plays a crucial role in DNA replication, proofreading and correcting errors. It works alongside DNA helicase and other enzymes to ensure accurate replication. When mistakes occur, the mismatch repair mechanism steps in post-replication to fix errors, preventing mutations and maintaining DNA integrity. Efrat Bruck video https://cdn.kastatic.org/googleusercontent/qz0-mYDuN8r3ON5BdLe5NSMQuD6QyZ-5x83zfuxHhbsd3WHUsdFBlUjFtsI5e9aPDctC6_sd-mNmb0kfhbww2Qg DNA repair 1 DNA polymerase III plays a crucial role in DNA replication, proofreading and correcting errors. It works alongside DNA helicase and other enzymes to ensure accurate replication. When mistakes occur, the mismatch repair mechanism steps in post-replication to fix errors, preventing mutations and maintaining DNA integrity. https://cdn.kastatic.org/ka-youtube-converted/o4yJF90OR9M.mp4/o4yJF90OR9M.mp4 676 Mechanism of DNA replication https://www.khanacademy.org/science/grade-12-biology-snc-aligned/xa8ba3a087f1f5288:reproduction-and-inheritance/xa8ba3a087f1f5288:mechanism-of-dna-replication/v/dna-repair-2 2023-08-14T21:12:46.061619254Z DNA repair 2 Let's continue to explore the fascinating world of DNA damage and repair. It explains how UV rays can cause pyrimidine dimers, leading to structural damage in DNA. The video also distinguishes between mutations and DNA damage, and explores both endogenous and exogenous factors that can cause DNA damage. Finally, it discusses the process of nucleotide excision repair and the potential consequences of faulty repair mechanisms.   Efrat Bruck video https://cdn.kastatic.org/googleusercontent/gWW9k1FmGDKlb1YIttocnTgKMjEnl6eLbwQebx3hTzLRMBWQFnhuerBm9dXiSS7KnqBJ2fJcknTE9Ph-LtfqJaWV DNA repair 2 Let's continue to explore the fascinating world of DNA damage and repair. It explains how UV rays can cause pyrimidine dimers, leading to structural damage in DNA. The video also distinguishes between mutations and DNA damage, and explores both endogenous and exogenous factors that can cause DNA damage. Finally, it discusses the process of nucleotide excision repair and the potential consequences of faulty repair mechanisms.   https://cdn.kastatic.org/ka-youtube-converted/PySVsEUnrng.mp4/PySVsEUnrng.mp4 558 Mechanism of DNA replication https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-replication/a/dna-proofreading-and-repair 2021-04-29T07:52:50Z DNA proofreading and repair Mechanisms to correct errors during DNA replication and to repair DNA damage over the cell's lifetime. article