科学达人秀

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! O" u5 }! B0 f) P. S       昨晚全程看了中国达人第二季总决赛直播，我觉得八个达人之所以那一刻能站在上海八万人体育馆的舞台中央，是因为他们都是自由而无用的人，他们的心灵是被上帝所亲吻过的。) C" F2 Y2 _8 J1 M5 @( J/ r& J
   尤其是胡启志的水晶球表演，我觉得在他身上能自如滚动的水晶球就像有生命一样的干细胞，透明晶亮而又无所不能。5 g6 W, n8 b8 a8 F4 @
   

laputave

回复 marrowstem 的帖子8 K7 Z" O0 h; R" H* |5 y
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是啊~~是那种对生命的感动和至爱~~
, R' m6 S, l3 Y: ]4 qLZ喜欢久石让的音乐否？我超爱的，他的音乐里总是充满了奇妙的东西~~" @. R# H! j# m
推荐lz欣赏一下撒~~

marrowstem

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. w, x/ X, X# u* t. n; C       其实在科学领域也有这些达人，可能最具代表性的是爱因斯坦，他在二十几岁只是一名专利局的小职员时写成了相对论，对时间和空间进行了新的诠释。, Q- f. J6 J4 j

marrowstem

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2 V: |; h5 v/ m8 E$ J9 a   在生命科学领域，个人觉得的达人是一对“互补达人”：沃森与克里克。
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    这两个算作半路出家的愣头青愣是打败了若干诺贝尔奖得主级别的竞争者而建立了DNA双螺旋结构的理论模型。您可别小看这两条“绳子”相互缠绕的螺旋，它可是现代分子生物学理论与技术的基础。
7 e; j4 E! Y* |  A4 }; h     分子生物学对于当代生命科学的意义怎么夸大也不为过，可以这么说，没有分子生物学，也就没有目前生命科学的一切。所以，沃森与克里克这一对达人组合在二十世纪可以傲视其他生命科学达人。而且他们的学术贡献远不止DNA双螺旋，他们还发现或；论证了DNA复制的原始模型和中心法则等，而这些全都成了世界教科书的经典内容。
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3 m% h$ R% `5 T: e) F" R4 Z达人牛文：$ L0 l3 z5 h+ l
1953年沃森与克里克发表在Nature杂志上的那篇轰动世界的classics paper
0 y  e# j5 }" w2 DMolecular structure of Nucleic acid+ W1 H, M; [1 C2 R
——A structure for Deoxyribose Nucleic Acid& |6 d  y5 U: B+ ~" o

2 \& K- O( ^! ~$ H# P" d5 Z. d& e8 dJ. D. Watson and F. H. C. Crick+ s" e4 R: Q' B' D# _' C1 D
（Medical Research Council Unit for the Study of the Molecular Structure of Biological Systems, Cavendish Laboratory, Cambridge）
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       We wish to suggest a structure for the salt of deoxyribose nucleic acid (D.N.A). This structure has novel features which are of considerable biological interest.
: \7 {+ s5 K" S& I2 v6 U       A structure for nucleic acid has already been proposed by Pauling and Corey[1]. They kindly made their manuscript available to us in advance of publication. They model consists of three inter-twined chains, with the phosphates near the fibre axis, and the bases on the outside. In our opinion, this structure is unsatisfactory for two reasons: 1)We believe that the material which gives the X-ray diagrams is the salt, not the free acid. Without the acidic hydrogen atoms it is not clear what forces would hold the structure together, especially as the negatively charged phosphates near the axis will repel each other. 2) Some of the van der Waals distances appear to be too small.
; r7 t' A! l% D1 y        Another three-chain structure has also been suggested by Fraser(in the press). In his model the phosphates are on the outside and the bases on the inside, linked together by hydrogen bonds. This structure as described is rather ill-defined, and for this reason we shall not comment on it.
2 C0 |, `: Q* K     We wish to put forward a radically different structure for the salt of deoxyribose nucleic acid. This structure has two helical chains each coiled round the same axis(see diagram), We have made the usual chemical assumptions , namely, that each chain consists of phosphate diester groups joining β-D-deoxyribofuranose residues with 3’,5’ linkages. The two chains (but not their bases) are related by a dyad perpendicular to the fibre axis. Both chains follow right handed helices, but owing to the dyad the sequences of the atoms in the two chains run in opposite directions. Each chain loosely resembles Furberg’s[2] model No.1; that’s , the bases are on the inside of the helix and the phosphates on the outside. The configuration of the sugar and the atoms near it is close to Furberg’s “standard configuration”, the sugar being roughly perpendicular to the attached base. There is a residue on each chain every 34A, in the z-direction. We have assumed in the same chain, so that the structure repeats after 10 residues on each chain, that is, after 34A. The distance of a phosphorus atom from the fibre axis is 10A. As the phosphates are on the outside ,cations have easy access to them.
9 [! E/ W; Z$ b/ I; [! G- _+ l       The structure is an open one, and its water content is rather high. At lower water contents we would expect the bases to tilt so that the structure could become more compact.7 D* U8 D$ |" \4 r$ m# L7 C( M) g
      The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bases. The planes of the bases are perpendicular to the fibre axis. There are join together in pairs, a single base from one chain being hydrogen-bonded to a single base from the other chain, so that the two lie side by side with identical z-co-ordinates. One of the pair must be a purine and the other a pyrimidine for bonding to occur. The hydrogen bonds are made as follows: purine position I to pyrimidine position I ; purine position 6 to pyrimidine position 6.9 z6 ]7 v" |) h8 y: N& T( D
        If it is assumed that the bases only occur in the structure in the most plausible tautomeric forms(that is , with the keto rather than the enol configurations)it is found that only specific pairs of bases can bond together. These pairs are: adenine(purine) with thymine (pyrimidine), and guanine(purine) with cytosine(pyrimidine).
  C3 F/ E) a0 i( r      In other words, if an adenine forms one member of a pair, on either chain, then on these assumptions the other member must be thymine; similarly for guanine and cytosine. The sequence of the bases on a single chain does not appear to be restricted in any way. However, if only specific pairs of bases can be formed, it follows that if the sequence of bases one chain is given, then the sequence on the other chain is automatically determined.8 P) M5 o( D6 A$ s  p
       It’s has been found experimentally that the ratio of the amounts of adenine to thymine, and the ratio of guanine to cytosine , are always very close to unity for deoxyribose nucleic acid.
/ T. S' a- Y3 {3 v4 S      It’s probably impossible to build this structure with a ribose sugar in place of the deoxyribose , as the extra oxygen atom would make too close a van der Waals contact.
2 p4 P  j- H2 L& s    The previously published X-ray data[5,6] on deoxyribose nucleic acid are insufficient for a rigorous test of our structure. So far as we can tell, it is roughly compatible with the experimental data, but it must be regarded as unproved until it has been checked against more exact results. Some of these are given in the following communications. We were not aware of the detail of the details of the results presented there when we devised our structure, which rests mainly though not entirely on published experimental data and stereo-chemical arguments., P  Q5 P) J6 C. t0 O2 k
       It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for genetic material.: \3 R) C8 j+ _9 g7 l- ^
         Full details of the structure , including the conditions assumed in building it, together with a set of co-ordinates for the atoms, will be published elsewhere.
; c% _# b; a& m" x4 E# ]/ s          We are much indebted to Dr.Jerry Donohue for constant advice and criticism, especially on inter atomic distances. We have also been stimulated by a knowledge of the general nature of the unpublished experimental results and ideas of Dr. M.H.F.Wilkins, Dr. R.E.Franklin and their co-workers at King’s College, London. One of us(J.D.W)has been aided by a fellowship from the National Foundation for Infantile Paralysis.
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No.4356 April 25, 1953   NATURE
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呵呵，互补达人，这个我喜欢~~
$ \3 \! h  f) Z1 S, D2 y3 a% Y+ c8 m除了学科的互补，也需要发现力和推理能力哈，就像达尔文，一个拥有敏锐的眼光和思考的年轻人，在五年的环球航行后，提出“物种起源”这样一个挑战当时权威的想法~~~
8 y8 R9 G" i; O; k! M/ T3 ^) j可以说，他的这一思考，真的给整个人类社会带来了一个巨大的冲击波：生命来自哪？人类又是如何进化而来？…………

xiaoheilong

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- M9 {4 Y, b3 u$ m9 K2 Q" s, p自由意志的获得是人生最大的财富啊!
1 J3 ~7 `6 M+ S在人生的海洋上，最痛快的事就是独断独航，但最悲惨的却是回头无岸。------哥伦布

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5 B1 A$ T0 {; O8 j% d( m     毫无疑问，遗传学的奠基人，19世纪奥地利神学院的修道士孟德尔也是一个典型的科学达人。孟德尔出身贫寒农家，由于家境困难，没有读完大学，虽然喜欢自然科学，但为了摆脱生活所迫，他违心进入修道院，成为一名修道士。; R0 X$ O( B, v# F: e
    1857年夏天，孟德尔开始用34粒豌豆种子进行他自认为的研究工作，开始了被人称为“毫无意义的举动”的一系列实验，并持续了8年时间，所有的工作都在修道院的后花园完成。' B/ r' f6 A6 {9 U+ A  }+ H
    但他的工作及提出的遗传理论在当时并没有人能理解，他争取机会所作的演讲、发表的论文及寄给包括达尔文在内的信没有一个被人注意及得到反馈。直至他死后多年也没被重视。但孟德尔知道他自己工作的重要性，在晚年曾经对友人G·尼尔森说过：“等着瞧吧，我的时代总有一天会来临。”: b  \- c8 a/ P" J+ F: F0 ~8 w
  

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      如果说孟德尔是遗传学的奠基人，那么美国科学家摩尔根则是基因学说的创始人，gene一词就由他创造，翻译成基因一词则由他的学生谈家桢完成。* ~1 |, O  A) e2 ~& s5 A$ q
      如果说孟德尔发现生物性状是可以遗传的，那么摩尔根通过实验手段证明，生物性状是可以通过基因突变而改变的。在他的实验室里，除了几张破旧的桌子外，里面全是装满了千千万万只果蝇的几千个牛奶罐；1910年5月，在他的实验室里产生了一只奇特的雄蝇，它的眼睛不像同胞姊妹那样是红色，而是白的。这显然是个突变体，注定会成为科学史上最著名的昆虫。摩尔根极为珍惜这只白眼果蝇，将它装在瓶子里，睡觉时放在身旁，白天又带回实验室。虽然这只白眼雄果蝇长得很虚弱，但通过努力，最终同一只正常的红眼雌蝇交配以后才死去，并留下了带有突变基因的后代，以后又繁衍成一个大家系。
! b9 M; `8 i) f4 l9 }, }; g' T  千万不要小看了这只白眼果蝇，它为摩尔根这个实验室带来好几个诺贝尔奖的科学最高贵奖品。" t% ~2 \8 }. C- N: O7 T

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   玉米田里的孤独先知
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      摩尔根发现和证实基因是可以突变的，而另一位科学达人则发现基因也是可以“跳跃”的，她就是美国科学家，1983年诺贝尔奖获得者——芭芭拉·麦克林托克。
" ?7 N0 z: @+ ^. I2 l% u; I; u     她一生未婚，但对玉米情有独钟，几乎养了一辈子的玉米，通过观察玉米上的斑纹变化提出： 基因在染色体上是可以移动位置的，也就是说基因能“转座”，但这个观点在当时提出时受到遗传学家的一致反对，且被人嘲笑。因为按照传统的观念，基因在染色体上的位置是固定不变的，它们有一定的位置、距离和顺序，它们只可以通过交换重组改变自己的相对位置，通过突变改变自己的相对性质；但是，要从染色体的一个位置“跳”到另一个位置，甚至“跳”到别的染色体上，那是科学家们从来没有想过的，简直是闻所未闻。1 P1 h4 w, t; f
    由于与传统的遗传学观念背道而驰，这使她限于孤立无助的境地。人们用怀疑、惊讶的异样目光看待她。这位原来在美国遗传学界享有盛誉的女科学家（1944年被选为国家科学院院士，1945年担任美国遗传学会主席，曾获得多次国家奖励），经受了她一生中相当长时间的孤寂和苦闷，朋友和同事大都和她渐渐疏远，她只好离群索居，几乎成了孤家寡人。7 G9 l0 R+ d. G" C
   真理往往掌握在少数人手里，虽然麦克林托克和她的理论在很长一段时间被视为另类和异端。但她坚持自己的观点，疯了一样的继续种玉米；另外幸运的是她也活得足够长，在81岁高龄时终于独得当年的诺贝尔医学和生理奖，这是世界上第一位靠独自研究成果而获得诺贝尔奖的科学家。