Jarosite托福聽(tīng)力原文翻譯及問(wèn)題答案

Jarosite托福聽(tīng)力原文翻譯及問(wèn)題答案

一、Jarosite 托福聽(tīng)力原文：

NARRATOR: Listen to part of a lecture in an astronomy class.MALE PROFESSOR: There's been a lot of talk recently about life on Mars, at the level of microorganisms anyway, mainly because of a few important discoveries and inventions.

For example, one major discovery was that at one point water was present on Mars. How do we know? Well, in 2004, an exploration robot discovered jarosite there.Jarosite is a yellowish brown mineral with a crystalline structure that's also found on Earth. It contains iron, potassium and hydroxide.The interesting thing is that on Earth at least it needs highly acidic water to form.So we've got water or had it at one point. And since most planetary scientists believe that water is essential to life, the presence of jarosite means that one prerequisite for life was once present on Mars.But there's another thing about jarosite. One step in its formation on Earth involves microorganisms; they actually speed up the formation of jarosite dramatically. Now, theoretically it is possible for jarosite to form without the help of biological life forms. But we don't really know for sure if this happens 'cause, well, because every corner of Earth has some form of biological life.

But jarosite on Earth incorporates all kinds of microorganisms into its crystalline structure. So it's possible that if the jarosite on Mars was also formed with the help of microorganisms, we might be able to detect remnants of them in the samples we find. And we have instruments now that will enable us to try to do this. For example, there's a new instrument called the microfabricated organic analyzer, or M.O.A.The organic analyzer is an amazing tool. It will be able to collect soil samples and analyze them right there on Mars, pure, untouched samples.It will let us eliminate the risk we would take of contaminating the samples if they were brought back to Earth.And what they'll look for specifically in the soil is amino acids.Amino acids, as you may know, are the building blocks of proteins. In fact, there are twenty standard amino acids involved in making proteins and lots more that aren't.

And here's the important thing. Amino acids are what we call handed.They can exist in two forms, which are mirror images of each other like hands. Right and left hands have the same number of fingers in the same order plus one thumb.But right and left hands are not the same; they are mirror images. Well, like hands, amino acids can be right or left-handed. And the twenty that make up the proteins on Earth are all left-handed.Now, one reason the M.O.A., the organic analyzer is so impressive is that it tests not just for the presence of amino acids but also for the handedness of amino acids. If amino acids are found, it would be especially interesting if they show a prevalence of one type of handedness, either left, like amino acids on Earth, or right.

See, other physical processes in space, processes that don't involve living organisms, can create amino acids.But the ones synthesized through abiotic processes, which is to say not involving microorganisms, occur in equal numbers of right- and left-handed.

So, a prevalence of left-handed amino acids would indicate they were biological in origin, which would be amazing! A prevalence of right-handed ones—well, that would be really amazing!! Because the organisms that created them would be unlike anything we have on Earth, which produce only left-handed ones.

二、Jarosite 托福聽(tīng)力中文翻譯：

旁白：在天文學(xué)課上聽(tīng)一節(jié)課的一部分。男教授：最近有很多關(guān)于火星生命的討論，從微生物的角度來(lái)說(shuō)，主要是因?yàn)橐恍┲匾陌l(fā)現(xiàn)和發(fā)明。

例如，一項(xiàng)重大發(fā)現(xiàn)是火星上曾一度存在水。我們?cè)趺粗溃?004年，一個(gè)探測(cè)機(jī)器人在那里發(fā)現(xiàn)了黃鉀鐵礬。黃鉀鐵礬是一種黃褐色礦物，其晶體結(jié)構(gòu)也存在于地球上。它含有鐵、鉀和氫氧化物。有趣的是，至少在地球上，它需要高酸性的水才能形成。所以我們有水或者曾經(jīng)有過(guò)水。由于大多數(shù)行星科學(xué)家認(rèn)為水對(duì)生命至關(guān)重要，黃鉀鐵礬的存在意味著火星上曾經(jīng)存在過(guò)生命的先決條件。但關(guān)于jarosite還有另一件事。它在地球上形成的一個(gè)步驟涉及微生物；它們實(shí)際上大大加速了黃鉀鐵礬的形成。現(xiàn)在，理論上黃鉀鐵礬可以在沒(méi)有生物生命形式幫助的情況下形成。但我們并不確定這種情況是否會(huì)發(fā)生，因?yàn)榈厍虻拿總€(gè)角落都有某種形式的生物。

但地球上的黃鉀鐵礬將各種微生物結(jié)合到其晶體結(jié)構(gòu)中。因此，如果火星上的黃鉀鐵礬也是在微生物的幫助下形成的，我們就有可能在我們發(fā)現(xiàn)的樣本中檢測(cè)到黃鉀鐵礬的殘余物。我們現(xiàn)在有了能夠使我們努力做到這一點(diǎn)的工具。例如，有一種新的儀器叫做微加工有機(jī)分析儀，或稱(chēng)M.O.a。有機(jī)分析儀是一種神奇的工具。它將能夠在火星上采集土壤樣本并進(jìn)行分析，這些樣本是純凈的、未接觸過(guò)的。這將使我們消除如果樣品被帶回地球，我們將面臨的污染風(fēng)險(xiǎn)。他們會(huì)在土壤中特別尋找氨基酸。你可能知道，氨基酸是蛋白質(zhì)的組成部分。事實(shí)上，有20種標(biāo)準(zhǔn)氨基酸參與蛋白質(zhì)的合成，還有更多的氨基酸沒(méi)有參與。

這是重要的一點(diǎn)。氨基酸就是我們所說(shuō)的手。它們可以以?xún)煞N形式存在，就像手一樣，是彼此的鏡像。右手和左手有相同順序的相同數(shù)量的手指加上一個(gè)拇指。但右手和左手不一樣；它們是鏡像。就像手一樣，氨基酸可以是右手的也可以是左手的。地球上組成蛋白質(zhì)的20個(gè)都是左手的。現(xiàn)在，有機(jī)分析儀給人留下深刻印象的一個(gè)原因是，它不僅檢測(cè)氨基酸的存在，還檢測(cè)氨基酸的利手性。如果氨基酸被發(fā)現(xiàn)，如果它們顯示出一種慣用手的流行，無(wú)論是左撇子，就像地球上的氨基酸，還是右撇子，那將是特別有趣的。

看，太空中的其他物理過(guò)程，不涉及生物體的過(guò)程，可以產(chǎn)生氨基酸。但是通過(guò)非生物過(guò)程合成的，也就是說(shuō)不涉及微生物的，以相同數(shù)量的右手和左手出現(xiàn)。

因此，左旋氨基酸的普遍存在將表明它們是生物起源，這將是驚人的！慣用右手的人很普遍哦，那真是太神奇了??！因?yàn)閯?chuàng)造它們的有機(jī)體與我們地球上的任何生物都不一樣，地球上只有左手生物。

三、Jarosite 托福聽(tīng)力問(wèn)題：

Q1:1.What is the lecture mainly about?

A. Evidence proving that water was once present on Mars

B. Scientific analyses currently being done on mineral samples from Mars

C. Recent developments that could help determine whether life ever existed on Mars

D. An approach to determining whether amino acids on Earth originated on Mars

Q2:2.What was discovered on Mars that suggests water once existed there?

A. Microorganisms that can form only in the presence of water

B. A mineral that can form only in the presence of water

C. Proteins that have the same structure as proteins found on Earth

D. Large deposits of iron and potassium that can form only in the presence of water

Q3:3.How might jarosite found on Mars differ from jarosite found on Earth?

A. Mars jarosite and Earth jarosite might have been created by different processes.

B. Mars jarosite might have been formed without water.

C. Mars jarosite might not contain as much iron or potassium as Earth jarosite.

D. Mars jarosite might be more acidic than Earth jarosite.

Q4:4.According to the professor, what are two important capabilities of the microfabricated organic analyzer? [Click on 2 answers.]

A. It can accurately test for the presence of water.

B. It can analyze soil samples without returning them to Earth.

C. It can return soil samples back to Earth quickly.

D. It can determine the handedness of amino acids.

Q5:5.What point does the professor make about the twenty amino acids that occur in proteins on Earth?

A. They can be either right-handed or left-handed.

B. They were synthesized through abiotic processes.

C. They all have a crystalline structure.

D. They are all left-handed.

Q6:6.What would a prevalence of right-handed amino acids in mineral samples collected on Mars indicate?

A. That amino acids on Mars probably originated on Earth

B. That amino acids existed on Mars long before they existed on Earth

C. That a type of microorganism may have existed on Mars that is different from any on Earth

D. That left-handed amino acids are probably present in some minerals on Mars

四、Jarosite 托福聽(tīng)力答案：

A1:正確答案：C

A2:正確答案：B

A3:正確答案：A

A4:正確答案：BD

A5:正確答案：D

A6:正確答案：C

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