The main objective is to study in vivo and in vitro the structure of nuclei acids, viruses, nucleoproteins and chromosomes, and other significant biological structures such as red blood cells. Particular emphasis on the internal organization of nucleic acids, and in the case of red blood cells, (RBC), the internal organization of polymerized sickle cell hemoglobin (Hb S). This will be attempted by using the remarkable optical properties of nucleic acids, and proteins, (Heme and non-heme for the RBC) in their various chemical and physical states. The most important methods will be: a circular dichroism (CD) and flow oriented CD; b) circular dichroic microspectrophotometer; c) differential imaging polarization microscopy; d) fluorescence detected circular dichroism (FDCD); and e) scattered corrected CD by fluorscat and FDCD methods. g) Intensified images of fluorescent labeled nucleic acids. The above techniques will give information concerning the following properties: a) the interactions between the bases of the nucleic acids and protein complexes and the protein components with themselves in such biological structures as viruses, chromosomes and intact nuclei; b) the electric and hydrodynamic properties of the protein coats and the average orientation of nucleic acids in viruses, nucleoprotein -DNA and RNA aggregates and/or complexes, and the degree of coiling of nucleic acids in intact nuclei and intact cells.