BIOL1006 Lecture Notes - Lecture 8: Acetabularia, Growth Medium, Cell Potency
Document Summary
Avery experiments - found the transforming principle from griffith. "s experiments removed nearly all of the protein in s. pneumoniae, but transformation still occurred purified mixture contained elements close to that of dna, had same density taking out lipids/proteins didn"t stop transformation. Dna-digesting enzyme dnase stopped all transformations showed that dna provided hereditary material for bacteria. 1 believed that 4 types of nucleotides available in equal amounts, repeated purine - adenine or guanine pyrimidine - thymine (replaced by uracil in rna) or cytosine nucleotide - dna unit, each consists of 5-carbon sugar, phosphate group, base. 1 phosphate/hydroxide groups allow nucleotides to attach in long chains phosphodiester bond - holds nucleotides together. Erwin chargaff - showed that dna didn"t just repeat itself. 1 amount of adenine always equals amount of thymine amount of cytosine always equals amount of guanine. 3d shape of dna - shaped like staircase wrapping around a common axis.
