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1、第三章第三节,DNA的复制,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,问题探讨,生物亲子代之间是通过物质DNA连接的,那么亲代的遗传物质如何“多出一份”来传递给子代?是否像洗
2、相片似的,有一张底片就可以洗出许多相片来?,一、对DNA分子复制的推测,沃森和克里克 提出的遗传物质自我复制的假说-,半保留复制,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,二
3、、证明DNA进行半保留复制的实验(选学),DNA是肉眼看不到的,如何才能分辨DNA? 此实验的基本思路是什么? 此实验是如何区分亲代与子代的DNA分子的? 用CsCl密度梯度离心后重带、中带、轻带表示的DNA分子的双链构成是怎样的? 在整个实验的亲代、子一代、子二代细胞中提取的DNA离心的结果说明了什么?,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with
4、 Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,:解旋酶催化(全部解开),解旋,模板,(在DNA聚合酶的催化下,利用游离的脱氧核苷酸进行),复制,:以母链为模板进行碱基配对,母链(旧链) 子链(新链),复制后的DNA,同时进行(边解旋边复制),(半保留复制),两子代DNA分子完全相同,与原DNA分子也相同。复制后原DNA分子不再存在。,三、 DNA分子的复制过程,Evaluation only. Created with Aspose.Slides for .NET
5、3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,DNA复制总结,DNA复制过程的特点有哪些? DNA复制需要哪些条件? DNA复制的场所在哪? 在什么时间进行?,边解旋边复制,且为半保留,模板、原料、酶、能量,核DNA在细胞核。 质DNA在各自细胞器。,有丝分裂的间期; 减数第一次分裂
6、的间期,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,DNA的复制总结,这种复制方式有何意义? 能够准确复制的原因是什么?,使遗传信息从亲代传给了子代,从而保证了物种的相对稳定性
7、,保持了遗传信息的连续性,使种族得以延续。,DNA具有独特的双螺旋结构,能为复制提供模板; 碱基具有互补配对的能力,能使复制准确无误。,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd
8、.,需记忆的几个重要公式:,(1)A = T C = G A + G = C + T = A + C = T + G (嘌呤 = 嘧啶) (2)A1 + T1 A2 + T2 A + T (互补碱基之和之比相等) C1 + G1 C2 + G2 C + G (3) A1 + C1 A2 + C2 1 T1 + G1 T2 + G2 M A + C A + G T + G T + C (4)设:M 为复制所需碱基总数,n 为复制次数,x 为一个DNA中碱基个数。 则:M ( 2 n 1 )X,M 则:,若:,(两链之间,非互补碱基之和之比互为倒数),1,(DNA中,非互补碱基之和之比等于1),E
9、valuation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,巩固练习,1、 1个DNA分子经过4次复制,形成16个DNA分子,其中含有最初DNA分子长链的DNA分子有( ) A. 2个 B. 8
10、个 C. 16个 D. 32个 2、 DNA分子的复制发生在细胞有丝分裂的( ) A. 分裂前期 B. 分裂中期 C. 分裂后期 D. 分裂间期 3、 以DNA的一条链“ATC”为模板,经复制后的子链是( ) A. “TAG” B. “UAG” C. “TAC” D. “TUG”,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slide
11、s for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,巩固练习,4、 下列关于DNA复制的说法,其中不正确的是( ) A. DNA复制过程中需要酶的催化 B. DNA复制过程中需要的能量直接由糖类提供 C. DNA 分子是边解旋复制的 D. DNA 复制过程中两条母链均可作模板 5、 一DNA分子中的 C + G = 40 %,共有102个A。该DNA连续复制三次,需要供给鸟嘌呤脱氧核苷酸多少?( ) A. 68 B. 102 C. 476 D. 544,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,