Dihydropyran is synthesized by treating tetrahydrofurfuryl alcohol with an arenesul-fonic acid, ArSO3H. Propose a mechanism for this conversion.
April 12 &14 th DNA Packaging: -‐ DNA is very large (human genome is about 3 billion base pairs), but has to packaged in a very small cell. -‐ Chromatin is packaged to form chromosomes. Nucleosomes get packaged into a small fiber, then that is coiled further into filaments. DNA Properties: -‐ Hyperchromic effect: denatured, single stranded DNA absorbs light much better than native double stranded DNA. -‐ Melting Curve: at half of the maximum absorbance on an absorbance vs temperature graph, this midpoint is the “melting temperature”. This depends on ion concentration ( salt ins stabilize negative charges on DNA and increase melting point), pH of solution, and mole fraction of G-‐C bp. -‐ Denatured DNA can renature if it is cooled back below its melting point. Nucleic Acids & stabilization -‐ Stacking interactions: they are hydrophobic & van der Waals forces between aromatic portions