BI226 Lecture Notes - Lecture 5: The Double Helix, Circular Bacterial Chromosome, Dna Replication
Document Summary
Two general themes to genes at the molecular levels. The genetic function of dna flow directly from its molecular structure: knowledge of molecular structure of dna makes it possible to understand biochemical processes of genetics. All of the genetics functions of dna depend on specialized proteins that read the information in. Dna sequence: dna itself is chemically inert. F. meischer (1869)extracted nuclein from nuclei of human white blood cells: weakly acidic, phosphorus rich material. Chemical analysis of nuclein revealed that its major component was deoxyribonucleic acid (dna: contains deoxyribose, found in nucleus, and is acidic. Staining of cells revealed that dna localized almost exclusively within chromosomes: schiff reagent- stains dna red. Dna contains four kinds of nucleotides linked in a long chain. Phosphodiester bonds- covalent bonds joining adjacent nucleotides. Protein is made of 20 different subunits: more potential for creating different combinations, chromosomes contain more protein than dna. Bacterial transformation implicates dna as the substance of genes.
