BIOSC 0160 Lecture Notes - Lecture 2: Cytosine, Guanine, Thymine

• School: Pitt
• Department: Biological Sciences
• Course: BIOSC 0160
• Professor: Candice Damiani

Document Summary

Lecture 2 chapter 13: dna structure and function. Four key features of dna secondary structure: the outer edges are exposed in major and minor grooves. The major grooves are the bigger spaces and the minor groups are the smaller spaces and they are relevant to dna binding proteins. Chargaff"s ratio: clairified that dna was antiparallel and also we discovered the sugar phosphate backbone was on the outside not the inside. Major grooves and minor grooves are chemically distinct. For regulating gene expression/dna binding proteins specific to chemical structure on the outside. Watson and crick suggested: semiconservative replication: parental strands separate and each one is used as a template. Meselson-stahl experiment: uses e. coli and grows them in heavy radioactive nitrogen (15n) and then after the bacteria incorporates the heavy nitrogen in their dna, they switch it back to regular nitrogen. Everything that is new will have regular nitrogen and everything that is old will have 15n.