Biology 1201A Chapter 12: DNA Structure Ch.12
22 Nov 2016
School
Department
Course
Professor
Document Summary
In 1928, scientists didn"t know yet that dna carried genetic information, but they knew that there was something that could cause bacteria to transform from one type to another. Transformation is the conversion of a cells hereditary type by uptake of dna released by the breakdown of another cell. Dna has 4 components, adenine, thymine, cytosine, and guanine. Dna was discovered by oswald avery by studying 2 strains of streptococcus pneumoniae. A virus is an infectious agent that contains either dna or rna surrounded by a protein coat. Bacteriophages (phages) are viruses that infect bacteria. Adenine and guanine are purines- nitrogenous bases built from fused rings of carbon and nitrogen atoms. Thymine and cytosine are pyrimidines, built from a single carbon ring. Chargaff"s rule: number thymine= adenine guacine = cytosine. Sugar-phosphate backbone- deoxyribose sugars are linked by phosphate groups in an alternating pattern (sugar- phosphate-sugar-phosphate)
