BIOL239 Lecture Notes - Nuclear Membrane, Guanine, Purine
16 Oct 2011
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1869 identified nuclein" as a weakly acidic, phosphorous-rich material from the nuclei of human white blood cells. Its major component later turned out to be dna (deoxyribonucleic acid) Dna red, shows that it is almost exclusively located within the chromosomes. The discovery that dna was a chromosomal constituent did not establish that it had anything to do with genes. Many scientists at the time pointed to proteins as the likely genetic material. Use of bacteria to implicate dna as the substance of genes. Bacteria carry their genetic material as a single circular chromosome, without it being enclosed by a nuclear membrane (prokaryotes) 1923 frederick griffith performed studies with streptococcus pneumoniae. Two forms : smooth (s) which is wild-type rough (r) The ability of a substance to change the genetic characteristics of an organism. By 1929 two other labs had repeated the results of griffith.
