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13 Cards in this Set
- Front
- Back
Replication fork |
Y-shaped region where the parental strands of DNA are being unwound |
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Helicase |
An enzyme that unwinds and separates the parental DNA strands at the replication fork |
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Single-strand binding protein |
Binds to unpaired DNA strands after they have been separated by helicase, in order to keep them from rejoining |
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Topoisomerase |
Breaks, swivels and rejoins DNA parental strands ahead of the replication fork to relieve the strain caused by the untwisting of the double helix |
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RNA primer |
The initial (RNA) nucleotide chain produced during DNA synthesis; grows in 5' to 3' direction, along the DNA template from 3' to 5'; new DNA strand starts on the 3' end of the primer |
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Primase |
Synthesises RNA primer using parental DNA strand as a template |
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DNA polymerases |
Enzymes that catalyse the synthesis of new DNA by adding nucleotides to a preexisting chain |
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DNA polymerase I |
Replaces RNA primers with DNA |
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DNA polymerase III |
In E. coli, DNA pol III adds a DNA nucleotide to the RNA primer, then continues to add complementary DNA nucleotides to the DNA template strand |
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Leading strand |
The strand of parental DNA which is synthesised continuously, requiring only one primer to initiate the process |
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Lagging strand |
The strand of parental DNA that is synthesised discontinuously, in a series of Okazaki fragments (which each require a primer) |
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DNA ligase |
Forms a bond between Okazaki fragments |
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Telomeres |
Nucleotide sequences at the end of eukaryotic chromosomal DNA molecules that do not contain genes - prevent the mechanisms that activate when DNA damage is detected, leading to cell cycle arrest or cell death - act as buffer zone that protects against the effects of gene shortening |