Chapter 11 Problems

Chapter 11 Problems - Name Hellums Jessica Problems and...

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Name: Hellums, Jessica UTEID: JSH575 Problems and Questions for Chapter 11 Material C9: In bacterial origins of replication there are two important sequences, the DnaA box and an AT-rich region. The DnaA box functions as a binding site for a bunch of DnaA proteins that upon binding bend the DNA. This shape change puts pressure on the strand forcing the strands to separate. The AT-rich region is important because A and T are held together by only two hydrogen bonds while G and C are connected by three hydrogen bonds. The fact that the site has fewer bonds makes it easier to separate. The combination of the pressure to separate the strands by the DnaA proteins and the easier separation of them at the AT-rich region help initiate replication. C15A: DNA polymerase moves in the 5’ to 3’ direction when removing RNA primers and in the 3’ to 5’ direction when proofreading and removing mistakes following DNA replication. C16: A. Right B. Right Yes, it is necessary for the middle fragment to be there so that DNA pol I can extend the 3’ end of that fragment. DNA pol I cannot add nucleotides unless there is an existing 3’ end, which is only there after it removes the RNA primer with its 5’ 3’ exonuclease activity. If there was no fragment before it, then DNA pol I couldn’t remove the RNA primer therefore creating a 3’ end. C. DNA ligase functions at the junction between the left and middle fragments by forming a covalent bond between the last nucleotide of the left fragment and the first nucleotide after the area where the RNA primer has been replaced with DNA
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This note was uploaded on 04/07/2008 for the course BIO 325 taught by Professor Saxena during the Spring '08 term at University of Texas.

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Chapter 11 Problems - Name Hellums Jessica Problems and...

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