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  • You're facing a giant bowl

    你對著滿滿一大碗的

  • of energy packed Carbon Crunchies.

    活力碳素早餐脆片

  • One spoonful. Two. Three.

    一匙、二匙、三匙

  • Soon, you're powered up by the energy surge

    很快你就會因為你吃的餐點

  • that comes from your meal.

    能量飆升,充滿活力

  • But how did that energy get into your bowl?

    但是能量如何進到你的碗內?

  • Energy exists in the form of sugars

    能量以糖的形式存在

  • made by the plant your cereal came from,

    糖又從製成早餐榖片的植物而來

  • like wheat or corn.

    如小麥或玉米

  • As you can see, carbon is the chemical backbone,

    如你所見,碳是化學骨架

  • and plants get their fix of it

    而植物從我們呼吸的空氣中

  • in the form of carbon dioxide, CO2,

    以二氧化碳 CO2 的形式

  • from the air that we all breath.

    取得碳

  • But how does a plant's energy factory,

    但位於葉綠體基質中的

  • housed in the stroma of the chloroplast,

    植物能量工廠

  • turn a one carbon gas, like CO2,

    如何將單碳氣體如二氧化碳

  • into a six carbon solid, like glucose?

    轉變成六碳固體如葡萄糖?

  • If you're thinking photosynthesis, you're right.

    如果你想到光合作用,你就對了

  • But photosynthesis is divided into two steps.

    但光合作用又分成兩個步驟

  • The first, which stores energy from the sun

    第一步,把光能

  • in the form of adenosine triphosphate, or ATP.

    以三磷酸腺苷 ATP 形式儲存起來

  • And the second, the Calvin cycle, that captures carbon

    第二步,卡爾文循環捕捉碳

  • and turns it into sugar.

    並將之轉成糖

  • This second phase represents one of nature's

    這第二階段代表了大自然

  • most sustainable production lines.

    最永續的生產線

  • And so with that, welcome to world's most miniscule factory.

    因此,歡迎蒞臨世界最袖珍的工廠

  • The starting materials?

    起始材料?

  • A mix of CO2 molecules from the air,

    空氣中的二氧化碳分子

  • and preassembled molecules called

    混合預先裝配好的分子

  • ribulose biphosphate, or RuBP,

    稱為核酮糖-1,5-二磷酸,簡稱 RuBP

  • each containing five carbons.

    每一個分子都含五個碳

  • The initiator? An industrious enzyme named rubisco

    催化劑?一種勤奮的酵素 rubisco (二磷酸核酮糖羧化酶)

  • that welds one carbon atom from a CO2 molecule

    它將二氧化碳分子中的一個碳原子

  • with the RuBP chain

    接到 RuBP 鏈上

  • to build an initial six carbon sequence.

    產生最初為六碳的序列

  • That rapidly splits into two shorter chains

    然後急速地分裂成兩個較短的鏈

  • containing three carbons each

    各含三個碳

  • and called phosphoglycerates, or PGAs, for short.

    稱為3-磷酸甘油酸 或簡稱為 PGA

  • Enter ATP, and another chemical called

    ATP 及另一種化合物進入,稱做

  • nicotinamide adenine dinucleotide phosphate,

    菸草醯胺腺嘌呤二核苷酸磷酸鹽

  • or just NADPH.

    或就叫 NADPH

  • ATP, working like a lubricant, delivers energy,

    ATP 的功用就像潤滑劑,輸送能量

  • while NADPH affixes one hydrogen to each of the PGA chains,

    而 NADPH 在每個 PGA 鏈上加一個氫

  • changing them into molecules called

    將 PGA 轉變成另一種稱為

  • glyceraldehyde 3 phosphates, or G3Ps.

    甘油醛3-磷酸的分子,簡稱 G3P

  • Glucose needs six carbons to form,

    形成葡萄糖需要六個碳

  • made from two molecules of G3P,

    以兩個 G3P 分子製成

  • which incidentally have six carbons between them.

    而這種結合剛好有六個碳

  • So, sugar has just been manufactured, right?

    所以,糖就這麼製成了,是嗎?

  • Not quite.

    還沒有

  • The Calvin cycle works like a sustainable production line,

    卡爾文循環就像一條永續生產線

  • meaning that those original RuBPs

    也就是說那些原有的 RuBP

  • that kicked things off at the start,

    在循環開始時啟動反應的物質

  • need to be recreated by reusing materials

    需要以重複利用

  • within the cycle now.

    此循環中的物質來再生

  • But each RuBP needs five carbons

    但是每一個 RuBP 都要五個碳

  • and manufacturing glucose takes a whole six.

    而製造葡萄糖要六個碳

  • Something doesn't add up.

    這怎麼湊得起來呢?

  • The answer lies in one phenomenal fact.

    答案就在一項驚人事實裡

  • While we've been focusing on this single production line,

    就在我們專心在這條單向生產線時

  • five others have been happening at the same time.

    另外五條生產線也同時開工

  • With six conveyor belts moving in unison,

    總共六條輸送帶聯袂作用

  • there isn't just one carbon that gets soldered

    所以並不是僅加一個碳

  • to one RuBP chain,

    到一個 RuBP 鏈上

  • but six carbons soldered to six RuBPs.

    而是接了六個碳到六個 RuBP 上

  • That creates 12 G3P chains instead of just two,

    這樣就產生了 12 個 G3P 鏈 而不是僅僅 2 個

  • meaning that all together, 36 carbons exist:

    意思是加起來共有 36 個碳存在

  • the precise number needed to manufacture sugar,

    正是製造(一個)糖 及重建(六個) RuBP

  • and rebuild those RuBPs.

    所需要的數字

  • Of the 12 G3Ps pooled together,

    在這匯集在一起的 12 個G3P 中

  • two are siphoned off to form

    有兩個被抽掉用來形成

  • that energy rich six carbon glucose chain.

    充滿能量的六碳葡萄糖鏈

  • The one fueling you via your breakfast. Success!

    透過你的早餐幫你加油。成功!

  • But back on the manufacturing line,

    但回到生產線

  • the byproducts of this sugar production

    這條糖生產線的副產品

  • are swiftly assembled to recreate those six RuBPs.

    瞬間組裝以再製六個 RuBP

  • That requires 30 carbons,

    那需要 30 個碳

  • the exact number contained by the remaining 10 G3PS.

    正是餘下的 10 個 G3P 所含的數字

  • Now a molecular mix and match occurs.

    現在要開始分子混搭

  • Two of the G3Ps are welded together

    兩個 G3P 要結合在一起

  • forming a six carbon sequence.

    形成一個六碳序列

  • By adding a third G3P, a nine carbon chain is built.

    再加上第三個 G3P 後 就製成了一條九碳鏈

  • The first RuBP, made up of five carbons,

    由五個碳組成的第一個 RuBP

  • is cast from this,

    就從這條九碳鏈中脫離

  • leaving four carbons behind.

    留下四個碳

  • But there's no wastage here.

    但物要盡其用

  • Those are soldered to a fourth G3P molecule,

    這四個碳要加到第四個 G3P 分子上

  • making a seven carbon chain.

    成為一條七碳鏈

  • Added to a fifth G3P molecule,

    把其加到第五個 G3P 分子上

  • a ten carbon chain is created,

    一條十碳鏈就產生了

  • enough now to craft two more RuBPs.

    足夠再製作兩個 RuBP

  • With three full RuBPs recreated

    十個 G3P 裡只要五個就能再製

  • from five of the ten G3Ps,

    三個完整的 RuBP

  • simply duplicating this process

    只要再重複這個製程

  • will renew the six RuBP chains

    就能重生六個 RuBP 鏈

  • needed to restart the cycle again.

    供給重新啟動整個循環所需

  • So the Calvin cycle generates the precise number

    所以卡爾文循環生成

  • of elements and processes

    確切數量的原件和流程

  • required to keep this biochemical production line

    能讓這個生化生產線

  • turning endlessly.

    無休止運轉

  • And it's just one of the 100s of cycles

    而這僅是存在於自然界中

  • present in nature.

    上百個循環之一

  • Why so many?

    為什麼要這麼多循環?

  • Because if biological production processes were linear,

    因為如果生物生產流程是線性的

  • they wouldn't be nearly as efficient or successful

    就不會這麼有效率及成功的

  • at using energy to manufacture the materials

    使用能量來製造

  • that nature relies upon, like sugar.

    自然界仰賴的物質,如糖

  • Cycles create vital feedback loops

    各式循環產生重要的維生回饋圈

  • that repeatedly reuse and rebuild ingredients

    回饋圈儘可能

  • crafting as much as possible

    從地球的可用資源中精密製造

  • out of the planet's available resources.

    能不斷重覆利用及重建的材料

  • Such as that sugar,

    就像糖一樣

  • built using raw sunlight and carbon

    靠著使用原始的陽光及碳

  • converted in plant factories

    將其在植物工廠內轉變

  • to become the energy that powers you

    成為供給你動力的能量

  • and keeps the cycles revolving in your own life.

    並讓你生命中的各式循環繼續運轉

You're facing a giant bowl

你對著滿滿一大碗的

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B2 TED-Ed 生產線 循環 分子 能量 製成

【TED-Ed】大自然最小的工廠。卡爾文循環--凱西-西蒙頓 (【TED-Ed】Nature's smallest factory: The Calvin cycle - Cathy Symington)

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    VoiceTube posted on 2021/01/14
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