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Fig. 9-CO, Nucleic acid: how structure conveys information Genetic material Gene-chromosome 親子鑑定 ??? DNA-RNA- Protein deoxyribonucleic acid ribonucleic acid
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Nucleic Acids Nucleic acid:Nucleic acid: a biopolymer containing three types of monomer units –a base derived from purine or pyrimidine (nucleobases) –a monosaccharide, either D-ribose or 2-deoxy-D- ribose (nucleoside) –phosphoric acid RNA (Ribonucleic Acid) DNA (Deoxyribonucleic Acid) Nucleotide ( 核甘酸 )
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Fig. 9-1 Common nucleobases: primary structure
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Fig. 9-2, Less common nucleobases
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Fig. 9-3, Ribonucleoside & deoxyribonucleoside: -D-ribose and nucleobase N-glycosidic linkage N1-pyrimidine N9-purine
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Fig. 9-4, Adding phosphoric acid-nucleotide AMP, ADP, ATP Esterified
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Fig. 9-4a (1), p. 238
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Fig. 9-5, Polymerization 3’,5’-phosphodiester bond Sugar-phosphate backbone pApCpGpU
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Fig. 9-6, pd(TGCA)
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The DNA family tree fossil Ancient DNA amber (polynucleotides)
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Nucleic Acids Levels of structure –1°structure: the order of bases on the polynucleotide sequence; the order of bases specifies the genetic code –2°structure: the three-dimensional conformation of the polynucleotide backbone –3°structure: supercoiling –4°structure: interaction between DNA and proteins
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Fig. 9-7, Double helix- 1953-Watson & Crick-X ray One turn—3.4 nm 10 base pairs Negative charge Major & minor groove Antiparallel Complementary strand A=T, G=C secondary structure
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Fig. 9-8 1 6 1 2
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Fig. 9-9a, B-DNA-major: 10 bp-right-handed Z-DNA-GC rich left –handed A-DNA-11bp, not in vivo (dehydrated DNA), right handed
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Fig. 9-10,
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Fig. 9-11, GC rich Zigzag: 180 O
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Fig. 9-12, Best pairing (but not stacking) Helical twist Expose to water at minor groove
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Fig. 9-13, Stacking-propeller-twisted base pairs Eliminate water contact Ring portion is hydrophobic Stacking better than pairing
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Fig. 9-15, Supercoiled DNA-tertiary structure
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Fig. 9-16 Topoisomerase-type1: one strand type2: double strand DNA gyrase
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Fig. 9-17 Chromatin-DNA+ Protein (histone) Histone-positive charge H1, H2A, H2B, H3, H4 Nucleosome 150 base pairs and (H2A)2(H2B)2(H3)2(H4)2 Spacer region: 30-50 base pairs and histone 1 & others The structure of chromatin
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Insertion deletion Insertion and deletion Mutation rate around nucleosome Nucleotide changes
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Methylation and Acetylation of histones regulates expression of genes Gene off Gene on Disease and epigenetic states Cancer immune deficiencies Diabetes heart disease DNA methylation: shutting off
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Why identical twins are not identical Microarrays coded to show epigenetic differences DNA sequence is the same Gene expression DNA methylation—5-methylcytosine Turn off expression (in Z DNA)
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Fig. 9-18 DNA denaturation H bond, stacking Melting hyperchromicity OD260 nm
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Fig. 9-19 DNA denaturation PCR reaction (amplification of DNA)
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Fig. 9-20 Information transfer in cells Replication Transcription Translation
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Fig. 9-21 The role of mRNA in transcription snRNPs: snRNA + proteins mRNA: Small amount and Very short-lived 100-200 nts
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Table 9-1
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Fig. 9-22 Transfer RNA-cloverleaf 1 amino acid :1 tRNA or more 80 nts Stem and loop
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Fig. 9-23 Modified bases in transfer RNA
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Fig. 9-24 Three dimensional structure of tRNA 3 nucleotides: 1 amino acid
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Fig. 9-26 E. Coli 70S Reduce Mg 2+ dissociation reversible The structure of typical ribosome antibiotics
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Fig. 9-25 The analytical ultracentrifuge Sedimentation coefficient Svedberg unit (S) Molecular weight and shape
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Fig. 9-27 Secondary structure for 16S ribosomal RNA 1500 nts 500 KDa
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Micro RNA : Regulation of gene Expression dsRNA (siRNA): Used by scientists to knock down a gene Adopted from giuworld.com
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The human Genome project 3.3 billion base pair 30,000 genes (25,000) Ethical Legal Social implications Gene therapy Genome on a ID card Synthetic genome created (2009) Watermark—blue colonies
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