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18 Cards in this Set
- Front
- Back
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is a fundamental process that occurs in all living organisms that copies their DNA.
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DNA replication
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DNA replication begins at specific locations in the genome, called
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origins
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unwinding of DNA at the origin, and synthesis of new strands, forms a replication fork.
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replication fork
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the enzyme that synthesizes the new DNA by adding nucleotides matched to the template strand, a number of other proteins are associated with the fork and assist in the initiation and continuation of the DNA synthesis.
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DNA polymerase
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Separates the two strands of DNA at a replication fork. Makes a small portion of the ds DNA into ssDNA. Allows binding of primase to make primers. Stabilized by single stranded binding proteins (SSB)
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Helicase
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Remove positive supercoils produced by DNA unwinding in front of the replication fork.
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Topoisomerase
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DNA polymerase cannot synthesize DNA de novo (from scratch) without a short strand to start with. Therefore, needs a primer (short strands of a few nucleoside) to get started. A RNA polymerase-makes short RNA primers on DNA template.
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Primase
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Junction between separated template strand and unreplicated DNA duplex.
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replication fork
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DNA synthesized 5' PO4'- 3'OH. Nucleophilic (bond by donating electrons) attack of a-phosphate of dNTP extends DNA.
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Replication elongation
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Continuously replicated new strand '5 to 3'
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Leading strand
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New DNA synthesized from other ssDNA (other direction?)
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Lagging strand
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Transient intermediates, short fragments of new DNA
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Okazaki fragments
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Uses a single site to catalyze addition of deoxynucleoside triphosphates (dNTPs)
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DNA polymerase
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Monitors base pairing by geometry. Proofreading ability.
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DNA polymerase
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Removes RNA primer. Degrades hybrid RNA:DNA, leaving a gap in the dsDNA
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Rnase H
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Fills in the gap with DNA except the break in the backbone between the 3'OH and the 5'PO4
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DNA polymerase
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repairs the "nick"with a phosphodiester bond between 5'PO4 AND 3' OH
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Ligase
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are required to separate in daughter DNA just after DNA replication of a circular chromosomes.
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Type II topoisomerases
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