BI226 Lecture Notes - Lecture 5: Dna Replication, Semiconservative Replication, Dnaa
Document Summary
Dna is the hereditary molecule of life: molecular substance that carries and conveys the genetic info of an organism. Gene composition: dna is made up of four sub-units, protein is made up of 20 sub-units, chromosomes contain more protein than dna. It attaches to bacteria, injects its genes into host cell, dna replicates and proteins are made, new phage particles assemble, cells burst releasing these new phage. Hershey-chase blender experiment: used radioactive tracers to mark if proteins or dna are the genetic material injected into host cells by bacteriophage, dna has no sulfur groups in it, protein has no phosphate groups, studied e. coli. Labelled dna in one experiment, and protein in the other. In the first experiment, radioactivity was discovered inside the cell, in the second experiment radioactivity was discovered in the ghost phage attached to the side of the cell. Dna"s chemical makeup: deoxyribose, one less oxygen than ribose, phosphate, four nitrogenous bases, pyramidines: t and c.
