BIOL107 Lecture Notes - Lecture 16: Helicase, Topoisomerase, Primase

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL107
• Professor: Frank Nargang

Document Summary

Strands are held together by weak h-bonds (easy to separate) and strands are complementary. Both daughter molecules are genetically identical to the parent and contain one old and new strand of dna. Dna strands were placed in a 15n culture and then transferred to a 14n culture. They were centrifuged after one, two and three replications of dna. Arthur kornberg identified dna polymerase, an enzyme capable of synthesizing dna. Dna polymerase requires magnesium ions, deoxynucleotide triphosphates (datp, dgtp, dctp, dttp), a free dna 3" end. In dna replication, the po4 on the 5" end of a carbon oh of the 3"end. **2 phosphates are lost and the oh loses an h (exergonic reaction that powers polymerization) Coupling of this exergonic reaction (the loss of the phosphates) is necessary for polymerization because we are putting nucleotides together to create order. Dna synthesis occurs in the 5" to 3" direction. Dna polymerase detects correct base pairing and adds the correct nucleotides.