Wednesday, 7 March 2012

BIO 12: UNIT 1 STUDY NOTES

DNA Replication

--> STEP I: 
    • Enzyme DNA Helicase unzips and unwinds the DNA double helix (i.e. H bonds are broken resulting in two separate strands of DNA), these two individual strands are known as DNA templates
--> STEP II:
    • Enzyme DNA Polymerase forms covalent bonds between the sugar and phosphate molecule (DS) and helps create the nucleotides of DNA by aiding with complimentary base pairing: free-floating nucleotides attract to their base pairs (leading strand = continuous, lagging strand = okagasaki fragments, shorter portions are joined)
--> STEP III:
    • Enzyme DNA Ligase acts as the glue to adhere the base pairs together with H Bonds, this is the last step in creating the finished DNA double-helix
****THE END RESULT IS TWO IDENTICAL COPIES OF DNA THAT ARE CONSIDERED SEMI-CONSERVATIVE BECAUSE ONE STRAND IS FROM THE ORIGINAL PARENT DNA AND THE OTHER IS THE NEW DAUGHTER STRAND FROM DNA REPLICATION (THE FREE FLOATING NUCLEOTIDES WHICH ATTRACTED TO THE PARENT STRANDS)****

* DNA Replication MUST occur for Cell Division to occur in providing each daughter with a copy of the DNA molecule and many copies of DNA must continuously be created for the vitality and functionality of a cell


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