3Chromosome Structure Section 12-2 Nucleosome Chromosome DNA double helixCoilsSupercoilsHistonesGo to Section:
4Key Idea 2 Organisms inherit genetic information in a variety of ways that result in continuity of structure and function between parents and offspring.2.1 f In all organisms, the coded instructions for specifying the characteristics of the organisms are carried in DNA, a large molecule formed from subunits arranged in a sequence with bases of four kinds (represented by A, G, C and T). The chemical and structural properties of DNA are the basis for how the genetic information that underlies heredity is both encoded in genes (as a string of molecular “bases”) and replicated by means of a template.
5Bases (rungs of the ladder) in DNA Purine BasesAdenine (A) and guanine (G)are the larger of the two types of bases found in DNA.
6Bases (rungs of the ladder) in DNA Pyrimidine Bases
7The DNA backbone is a polymer with an alternating deoxyribose sugar-phosphate sequence DNA (deoxyribonucleic acid) is a double-stranded molecule that is twisted into a helix like a spiral staircase
8Base Pairing in DNAA with T: the purine adenine (A) always pairs with the pyrimidine thymine (T)C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)Give instructions to make the DNA molecule