DNA and the Gene

Initiation of replication takes place at the corder

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Unformatted text preview: lication bubbles grow as DNA replication proceeds, because synthesis is bidirectional – it occurs in both direction at the same time. Bacterial chromosomes have a single location where the replication process begins and forms a single bubble. Specific proteins is responsible for recognizing sites where replication begins and opening the double helix at those points. Activated by the proteins that initiate S phase in the cell cycle. Initiation of replication takes place at the corder of each replication bubble: replication fork. Y shaped region, where the parent DNA double helix is plit into two single strands. Helix opens when an enzyme called helicase breaks the hydrogen bonds between deoxyribonucleotides. (Cuts between the complementary base pairings) Single- strand DNA- binding proteins (SSBPs) attach to the separate strands to prevent them from snapping back into a double helix. The untwisting movement at one end would force the intact section to rotate in response. This tension is relieved by proteins called topoisomerases. It cuts DNA, allowing it to unwind, and rejoins it ahead of the advancing replication fork. Leading strand is synthesized with the help of a primer, which consists of a new nucleotides bonded to the template strand, because it provides...
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