3 Chromosome Structure Section 12-2 Nucleosome Chromosome DNA double helixCoilsSupercoilsHistonesGo to Section:
4 Key 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.
5 Bases (rungs of the ladder) in DNA Purine BasesAdenine (A) and guanine (G)are the larger of the two types of bases found in DNA.
6 Bases (rungs of the ladder) in DNA Pyrimidine Bases
7 The 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
8 Base 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
9 DNA Nucleotides Purines Pyrimidines Adenine Guanine Thymine Cytosine Section 12-1PurinesPyrimidinesAdenineGuanineThymineCytosinePhosphate groupDeoxyriboseGo to Section:
10 Structure of DNA Nucleotide Hydrogen bonds Sugar-phosphate backbone KeyAdenine (A)Thymine (T)Cytosine (C)Guanine (G)Go to Section:
11 Transcription – making RNA Section 12-3Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)RNA polymeraseRNADNAGo to Section: