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Unite four Nucleotides and Nucleic acids 05 级生物技术一班 游琼英 20052503420
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Nucleic acidnucleotide phosphate Nucleoside base Pentose ( 戊糖 ) { {
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Base contain three kinds of Pyrimidine( 嘧啶 ) and two kinds of Purine( 嘌呤 )
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five main kinds of base 胞嘧啶 脲嘧啶 胸腺嘧啶
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腺嘌呤 鸟嘌呤
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Complementary strands of DNA,two polynucleotide chains associate by base pairing to form double-stranded DNA, A pairs with T, and G pairs with Cby forming specific hydrogen bonds,
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PENTOSE Ribose( 核糖 ) H Deoxy-ribose( 脱氧核糖 ) Can you find the differences between they ?
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D-ribose (in RNA) 2-deoxy-D-ribose (in DNA) The difference - 2'-OH vs 2'-H This difference affects secondary structure and stability About ribose and deoxy-ribose
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nucleoside they link to each other at 9 and 1’
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They connect with each other both at 1 and 1’
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Nucleic acids Polymers linked 3' to 5' by phosphodiester bridges Ribonucleic acid and deoxyribonucleic acid Know the shorthand notations Sequence is always read 5' to 3' In terms of genetic information, this corresponds to "N to C" in proteins
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The backbone structure Phosphodiester bridge( 磷酸二酯键 )
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Phosphodiester bridge( 磷酸二酯键 ), 1\convant bones 2\link a nucleic acid reside to another 3\3’-OH to 5’-OH
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The simple one From 5’ end to 3’end 5’end 3’ end
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The basic feature of B-DNA Remember that there have 5 features and 6 parameters 1. Double-Helix is Antiparallel Two Chains Right Helix The diameter of the helix in B-form DNA is 2 nm 2. Deoxyribose-phosphate (脱氧核糖 - 磷酸) backbone lies on the outside and bases on the inside Parameter 2 : A Rotation ( 转角 ) of 36 Degrees Per Base Parameter 3: Adjacent Bases are Separated by 0.34nm Parameter 4 : 10 Base Pairs Per Turn Parameter 5 : 3.4 nm Per Repeat Base Obliquity (碱基倾角) 0 Degree 3. Two Kinds of Grooves in the Surface 大沟 (major groove) ,小沟 (minor groove) 4. Bases are Restricted Pairing on the Inside 5. A Pair of Chains are Complementary Sequences B form DNA is the most usual one in the six forms of DNA
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What forces make they together? 1. Horizontal power—hydrogen bond (氢键) 2. Perpendicular power — the stacking of bases (碱基堆积力) 3. Neutralising negatively charged phosphates of two chains — ion bond (离子键)
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Restriction endonuclease( 限制性内 切酶 ) Come from bacteria can recognize the specific sequence Cut the DNA into pieces Contain palindromic structure( 回文结构 )
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1\The restriction endonuclease can recognize the specific sequence 2\agglutinate together by “sticky” ends( 粘 性末端 ) Being used in DNA cloning and termination( 测序 )
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Chain termination method ( 末端测序 法 ) Base on DNA polymerase reaction Run for four separate reactions Contain dATP, dCTP, dGTP, dTTP Also contain ddATP,ddCTP,ddGTP,ddTTP,one of which is P-32-labelled.
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