BIOL 2111 Chapter Notes - Chapter 5: The Double Helix, Bacteriophage, Nitrogenous Base
28 Oct 2016
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Chapter 5: the multifaceted nature of the dna molecules. After purifying dna from the nuclein and performing chemical test, researchers establish that it contained only four distinct chemical building blocks linked in the long chain. Four individual chemicals belong to class of compounds known as nucleotides. Bacterial transformation implicates dna as the genetic material. Griffith suggested 2 bacterial forms: smooth (s) and rough (r) S is the wild type, a mutation in s gives rise to r. S appears smooth because they synthesize a polysaccharide capsule that surrounds pairs of cells: r forms are unable to make capsular polysaccharide. Be(cid:272)ause pol(cid:455)sa(cid:272)(cid:272)haride (cid:272)apsule helps prote(cid:272)t the (cid:271)a(cid:272)teria fro(cid:373) a(cid:374) a(cid:374)i(cid:373)al"s i(cid:373)(cid:373)u(cid:374)e response, s bacteria are virulent. Ability of a substance to change genetic characteristics of an organism is known as transformation. Avery and his coworkers eventually prepared a tangible active transforming principle. A long whitish wisp materialized from ice cold alcohol solution and wound around the stirring rod.
