November 29 Lecture Notes

November 29 Lecture Notes - Bio Lecture Notes Replication...

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Bio Lecture Notes November 29, 2006 Replication DNA – Semi conservative replication. The helicases is the enzyme the unwinds the DNA. But, when you try to unwind it there can be knots and things like that and then there is this enzyme… topoisomerases… that basically cuts the DNA and then heals it again… Each subunit that makes up the DNA, has a base, three phosphates and a nitrogen. You lose two of the phosphates and then the one that is remaining becomes apart of the backbone. (what kind of reaction could this be…. Since we are making something, and losing the phosphates, it is exergonic…lose of phosphate drives the reaction) The two strands of DNA are anti-parallel to one another. They run in opposite directions. But each strand has polarity. If you look at the sugar molecules in each strand, you’ll see that in one strand the sugar molecule’s roof ( ^ ) are facing one way and the opposite in the other strand. There are rules for numbering the carbons in molecules. SO the carbons in the bases and the carbons in the sugars have to be mentioned. But at the same time you also have to indicate when your talking about a base carbon or a sugar carbon. In the molecular is made like this… there is a 3 carbon sugar covalently bonded to a phosphate and that is then covalently bonde to another sugar. . etc. But at one end of the molecule there is a 3’ (3 prime) at one end of the strand, but there is a 5’ (5 prime) at the other end. BECAUSE THE STRANDS ARE ANTI-PARALLEL, if you know the designation of one of the strands, then also know the designation of the other ends as
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This note was uploaded on 04/04/2008 for the course BIO 101 taught by Professor Martin during the Fall '08 term at Rutgers.

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November 29 Lecture Notes - Bio Lecture Notes Replication...

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