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  • Geckos and grasshoppers, worms and watermelons,


  • elephants and Escherichia Coli,


  • man and mushroom. All so different in form and function,

    人和蘑菇。 全部都具有不同外型和功能,

  • but amazingly the same in how their form and function are determined.

    但卻神奇地藉由 相同方法決定外型與功能。

  • First, all these organisms are made of one or more cells,

    首先,這些生物都 具有一個以上的細胞,

  • and every cell of every living thing on earth


  • contains all the information it takes


  • to create and duplicate and make variations of itself.


  • That information is stored in a very long but quite simple

    這些訊息存在 一條很長卻很簡單的雙分子,

  • double molecule called DNA,

    稱為 DNA,

  • or Deoxyribonucleic Acid.


  • And the DNA of every living organism is made of chains of four smaller molecules

    不同生物的 DNA 皆是由四種小分子組成

  • called nucleotides. What dictates the difference between a man and a mushroom

    它們被稱為核苷酸。 而就是 DNA 上不同的核苷酸組成

  • is the sequence of these nucleotides in the long DNA chain.


  • The four differing nucleotide parts, called bases,


  • are made of a few carbon, oxygen, hydrogen, nitrogen and phosphorus atoms,


  • and the molecules look like this.

    完整分子長得像這樣。 (譯注:這是兩個配成對的核苷酸)

  • And each of these four bases is attached to an identical backbone molecule,


  • a sugar called deoxyribose - the "D" in DNA - and a phosphate group.

    這被稱為去氧核糖, 也是 DNA 中 D 所代表的糖和磷酸根。

  • Let's simplify these nucleotides and show them like this.


  • So, a single sequence of nucleotides joined by their common sugars would look like this.

    在同一股上的核苷酸以 同樣一種去氧核糖連結成長鏈。

  • And the DNA molecule where such sequences are stored looks like this.

    而保存核苷酸序列資訊 的 DNA 分子則長成這樣。

  • But how does a simple molecule dictate the form and function of millions of different living things?

    但單一分子如何決定 不同生物的形式與功能?

  • You can think of DNA as a great library of information,

    你可以把 DNA 想成 儲存資訊的大圖書館,

  • information that is used to do one thing and one thing only:


  • direct the building of different protein molecules.


  • And it's the proteins that build the cells and keep them functioning

    蛋白質可以建構細胞 並讓細胞執行功能、改變與增生。

  • and changing and reproducing. Here's where the familiar word 'gene' comes in.


  • If your DNA is a library of information, a gene is a book in that library.

    如果 DNA 是圖書館,基因就是裡面的書。

  • A gene is a segment of the DNA molecule.

    基因就是一小片段的 DNA。

  • Let's say your body needs a particular protein, like insulin.


  • To get it, some of your cells send a protein signal through the bloodstream


  • to the cells in your pancreas, where insulin is made.

    藉此傳達到胰臟細胞, 也就是負責製造胰島素的地方。

  • That signal protein tells other proteins in the cell's nuclei

    這個訊號蛋白質會 告訴細胞核內的其他蛋白質

  • to open up a part of the DNA double helix, the insulin gene,

    打開 DNA 上胰島素基因的雙股螺旋

  • and start making insulin proteins.


  • As soon as enough insulin has been produced,


  • another signal protein comes to the pancreas' cells that tells them to stop making insulin.

    另一個訊號蛋白質會 告訴胰臟細胞停止製造。

  • It's like looking up a book in the DNA library about insulin,

    這就在 DNA 圖書館裡 像看一本關於胰島素的書,

  • and then putting it back when you're done.


  • There are genes in DNA for visible and invisible things that make up your body,

    你身體可見與不可見的部份 都由基因決定,

  • like genes for eye color, protein pigments, for skin color,

    像是眼睛的顏色及色素蛋白、 膚色、髪色、

  • for hair color, for stopping and starting bone growth,


  • for your blood type, for how many fingers or arms and legs you have,


  • for proteins that influence how long you live.


  • Your DNA probably contains between 25 thousand and 40 thousand genes,

    你的 DNA 大約包含 2.5 到 4 萬個基因,

  • while the DNA of a worm or a plant or a fruit fly

    而蠕蟲、植物或是果蠅的 DNA

  • contains about 12 thousand to 20 thousand genes.

    大約包含 1.2 到 2 萬個基因。

  • Some of those genes have quite different sequences of nucleotides than yours,


  • and some are similar to yours.


  • Though it happens infrequently,


  • our own nucleotide sequences can change


  • as the result of spontaneous or environmental damage

    常會因為自發性 或環境的傷害

  • which might remove or shift a nucleotide position.


  • This changes the gene involved, and can then change the protein.


  • Most of these changes, called mutations,


  • have very little effect on the organism or its descendants.


  • some are mildly damaging,


  • and a few can make the organism better-suited to its environment.


  • It is these tiny changes in DNA gene sequences, happening over millions of years,

    而就是數百萬年來 累積在 DNA 序列上的變異,

  • that create the differences among living organisms, from geckos to grasshoppers.

    造成了不同種的生物 ──從壁虎到蚱蜢,

  • worms to watermelons, elephants to Escherichia Coli, and man to mushroom.


Geckos and grasshoppers, worms and watermelons,


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B2 中高級 中文 TED-Ed 蛋白質 基因 胰島素 分子 細胞

【TED-Ed】DNA 的故事 - The twisting tale of DNA - Judith Hauck

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    VoiceTube 發佈於 2013 年 05 月 02 日