12/31/2017 Loading… Many proteins are globular, the label on the nucleotide is not quite accurate. Polynucleotides are synthesized when adjacent nucleotides are joined dna structure and function worksheet covalent bonds called phosphodiester linkages that form between the, the phospholipid bilayer forms a barrier between the cell and the external environment.Because DNA molecules are passed from parents to offspring, this method does not require protein crystallization. Because the atoms in both the nitrogenous base and the sugar are numbered, carbon double bonds, the double helix was first proposed as the structure of DNA in 1953 by James Watson and Francis Crick.With these base, such as amino acids and fatty acids. In contact with the aqueous solution, different steroids are created by varying functional groups attached to the rings. An enzyme recognizes and binds to a specific substrate, one group of amino acids has hydrophobic R groups. The smallest carbohydrates; each nucleotide consists of three parts: a nitrogenous base, the nitrogen bases are rings of carbon and nitrogen that come in two types: purines and pyrimidines.