Florence (Firenze) 10 day weather forecast, updated four times a day and shows the weather summary plus detailed sun, rain, snow, wind and temperature. The weather forecast extends out to 10 days showing information for morning, afternoon and overnight.
Definition of double helix. : a helix or spiral consisting of two strands in the surface of a cylinder that coil around its axis; especially : the structural arrangement of DNA in space that consists of paired polynucleotide strands stabilized by cross-links between purine and pyrimidine bases â compare alpha-helix, watson-crick model.
1 In biology, double helix is a term used to describe the structure of DNA. A DNA double helix consists of two spiral chains of deoxyribonucleic acid. The shape is similar to that of spiral staircase. DNA is a nucleic acid composed of nitrogenous bases (adenine, cytosine, guanine and thymine), a five-carbon sugar (deoxyribose), and phosphate molecules.