DNA replication

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Helicase
An enzyme that untwists the double helix of DNA at the replication forks
replication bubble
a region of DNA, in front of the replication fork, where helicase has unwound the double helix
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
origin of replication
Site where the replication of a DNA molecule begins, where the two nucleotides are separated, opens replication bubble
RNA primase
An enzyme that creates an RNA primer for initiation of DNA replication and attaches it
RNA primer
short segment of RNA used to initiate synthesis of a new strand of DNA during replication
Topiosomerase
Keeps dna stable
DNA polymerase I
removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides
DNA polymerase III
adding bases to the new DNA chain; proofreading the chain for mistakes
Ligase
An enzyme that connects two fragments of DNA to make a single fragment
semiconservative
method of replication that implies that each new strand of DNA is half original and half new , parent strand acts as templates for the new strands
Olkazaki fragment
Short fragment of DNA found in the lagging strand
Backbone of DNA
The backbone is comprised of alternating pairs of Sugars (Deoxyribose) and Phosphate groups.
Can only add new bases on
3' strand
Order
DNA, rna, protein, phenotypes, you
~ means
High energy bond
Phosphodiester bond
Bond between phosphate and sugar
glycocidic linkage
Sugar bonded to nitrogenous bases
Limitations of dna polymerase
Creates problems for linear dna of eukaryotic chromosomes, at each replication it produces shorter dna molecules with uneven ends
Telomeres
Repeating sequences of nucleotide sequence, TTAGGG with part overhanging of sequence, help to prevent erosion of genes near the end of the molecule, age us but may prevent cancer cells, in germ cells telomerase catalyze the lengthening of telomeres
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