BIOL 3305 Lecture Notes - Lecture 35: The Double Helix, Streptococcus Pneumoniae, Complementary Dna
Document Summary
Chapter 12 dna structure, replication and organization. Characterizing dna sequences can enhance our understanding of genetic history, but it is overshadowed by dna damage and contamination. The double helix of dna is subject to: breakages in one or both strands, lnappropriate cross-linking, chemical modification of individual bases. Dna can be maintained" via very cold temperatures, as ancient bacterial dna sequences have been recovered from 500000 year old sections of ice cores. Dna naturally degrades over time, so adna sequences remaining in a tissue sample are rare and prone to contamination, which is why handling dna needs to be done in a very clean, contaminant free fashion. 12. 1 establishing dna as the heriditary molecule. Proteins were believed to be hereditary molecules because they has 20 types of amino acids vs nucleic acids" 4 nitrogenous bases, so proteins seemed to offer greater opportunities for information coding.
