BIOL 1000 Chapter 12: CHAPTER 12 - DNA Structure, Replication, & Organization
8 Mar 2018
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In the very beginning, johann friedrich miescher extracted pus from discarded bandages and found that they have an acidic substance high phosphorus content called it nuclein; now dna. S-cells = virulent (smooth&shiny); r-cells = nonvirulent (rough: avery & coworkers: showed that dna (not protein or rna), is molecule responsible for transforming this s. pneumoniae bacteria into virulent form. Cultured bacteria and destroyed protein, rna & dna, and only dna had an effect and stopped transformation. People were shocked because they thought protein is the hereditary molecule as it has 20 diff. They studied t2 phage"s (only contains dna & protein) replication cycle and infected separate cultures of: coli w/ two types of labelled phages protein (radioactive isotope of sulphur) and. Only radioactive dna resulted in radioactivity in infected bacteria & none left in phage coats after blender. Term transformation was established: conversion of cell"s hereditary type by uptake of dna released by breakdown of another cell.
