Topic 1b- DNA replication Flashcards
What is the role of DNA helicase in DNA replication?
-Unwinding the double-stranded DNA molecule by breaking hydrogen bonds between complementary base pairs.
-Separating the DNA strands, allowing each strand to be copied.
-Loading at the origin of replication and moving the replication forks forward.
-Unzipping the DNA to separate the leading and lagging strands for replication to occur.
-Forming the replication fork.
What’s the key difference between the conservative and semi-conservative theories of DNA replication?
In conservative replication, both newly produced double helices contain entirely new DNA, while in semi-conservative replication, each strand of the two newly formed DNA has one old strand and one new strand.
Describe the process of semi-conservative DNA replication.
DNA helicase breaks the hydrogen bonds between the two DNA strands and the DNA helix unwinds. Each strand acts as a template for a new strand. Individual free DNA nucleotides join up along the template strand by complementary base pairing. DNA polymerase joins the individual nucleotides together, so that the sugar-phosphate backbone forms. Hydrogen bonds then form between the bases on each strand and the strands twist to form a double helix.
