Fungi托福聽(tīng)力原文翻譯及問(wèn)題答案

Fungi托福聽(tīng)力原文翻譯及問(wèn)題答案

一、Fungi托福聽(tīng)力原文：

NARRATOR:Listen to part of a lecture in an environmental science class.

FEMALE PROFESSOR:When you try to imagine a fungus,you probably picture a mushroom popping up out of the ground…and think that’s it.But a fungus like that…most of it actually lives underground.

And fungi in general are often an important active component of the soil.A fungus secretes enzymes into the soil,enzymes that break down…decompose organic material in the soil…so the fungus can absorb this material and get nutrition.

But to me what’s most interesting about this process is how it may enable fungi to help clean up environmental pollution in the soil…And that's thanks in part to a substance in their cell walls called chitin.

Now a lot of people think fungi are related to plants,but they're not.Believe it or not,the only other place chitin is found in abundance is in the exoskeletons of insects,crabs,and such!So,in this sense,fungi are more associated with insects than with any plant.Strange,huh?

And the chitin in the cell walls of a filamentous fungus…A filament,of course,is a long,threadlike structure—cells joined end to end.Filamentous fungi grow in soil and in decaying vegetation,and,as their name implies,they exist as filaments.And,although regarded as microorganisms,filaments from a single fungus can fan out to occupy many square meters or even several square kilometers of forest floor.Their vast surface area allows them to break down and take in huge amounts of nutrients.But beyond that,the filiments also pull out of the soil a great deal of the pollution that might be in there,especially heavy metals.

And here's where chitin comes in.Like some other substances in fungal cell walls,chitin forms strong chemical bonds to heavy metals in the environment…in a process we call adsorption.

Now don't confuse this with absorption,where a substance is absorbed into a cell,into the interior of a cell.I mean that's happening here too,but adsorption means binding to the outer surface of the cell.And a filamentous fungus can adsorb toxic heavy metals…bind them to the surface of its enormous network of filaments—and thereby detoxify a large soil ecosystem.The heavy metals are still there,but instead of leaching into the water system and contaminating the water underground,large amounts of these metals may remain bound to the chitin…to the cell walls of filamentous fungi in the soil…and thus remain chemically inactive for as long as thirty years—perhaps longer.

In fact,we can actually use the cell walls of filamentous fungi as a filter,even after the fungi are dead.

For example,the pharmaceutical industry grows filamentous fungi in large quantities in the lab.Like,to produce the antibiotic penicillin,the drug company grows the fungus Penicillium.And after the penicillin is extracted,these dead Penicillium filaments…we can use the chitin in their cell walls to make industrial filters to adsorb heavy metals.We can put these filters into waste pipes from industrial processes and use the filters to trap heavy metals,like mercury and zinc.Later,we can chemically extract the heavy metals and reuse the filter over and over.

Now,going back to the absorption of toxic metals into the body of the fungus,let's turn our attention to mushrooms.

Like other fungi,mushrooms can absorb large quantities of heavy metals.In fact,they may contain up to two-and-a-half times the concentration of toxic metals found in the soil they grow in.So mushrooms,at least what we see above ground…we can potentially harvest them and then,once and for all,safely dispose of the pollutants contained within them.

In fact,to clean up…especially the groundwater system…permanently,harvesting mushrooms is probably the best way to go.For some reason,this hasn't happened yet,as far as I know.But I can easily envision cultivating mushrooms for the sole purpose of detoxifying a large underground ecosystem.

二、Fungi托福聽(tīng)力中文翻譯：

旁白：在環(huán)境科學(xué)課上聽(tīng)講座的一部分。

女教授：當(dāng)你試著想象一種真菌時(shí)，你可能會(huì)想象一個(gè)蘑菇從地里冒出來(lái)……然后想就是這樣。但像這樣的真菌……大部分實(shí)際上生活在地下。

真菌通常是土壤的重要活性成分。真菌向土壤中分泌酶，分解酶……分解土壤中的有機(jī)物質(zhì)……因此真菌可以吸收這些物質(zhì)并獲得營(yíng)養(yǎng)。

但對(duì)我來(lái)說(shuō)，這個(gè)過(guò)程最有趣的是它如何使真菌幫助清理土壤中的環(huán)境污染……這部分要?dú)w功于它們細(xì)胞壁中一種叫做甲殼素的物質(zhì)。

現(xiàn)在很多人認(rèn)為真菌與植物有關(guān)，但事實(shí)并非如此。信不信由你，甲殼素在昆蟲(chóng)、螃蟹等動(dòng)物的外骨骼中也大量存在！因此，從這個(gè)意義上說(shuō)，真菌與昆蟲(chóng)的關(guān)系比與任何植物的關(guān)系都要密切。奇怪吧？

絲狀真菌細(xì)胞壁中的幾丁質(zhì)……當(dāng)然，絲狀結(jié)構(gòu)是一種長(zhǎng)的線狀結(jié)構(gòu)，細(xì)胞端對(duì)端連接在一起。絲狀真菌生長(zhǎng)在土壤和腐爛的植被中，顧名思義，它們以絲狀存在。而且，盡管被視為微生物，但單個(gè)真菌的細(xì)絲可以扇出，占據(jù)許多平方米甚至數(shù)平方公里的森林地面。它們巨大的表面積使它們能夠分解并吸收大量的營(yíng)養(yǎng)物質(zhì)。但除此之外，這些軟泥還會(huì)從土壤中帶走大量可能存在的污染，尤其是重金屬。

這就是幾丁質(zhì)的來(lái)源。像真菌細(xì)胞壁中的其他一些物質(zhì)一樣，甲殼素與環(huán)境中的重金屬形成強(qiáng)大的化學(xué)鍵……這一過(guò)程我們稱之為吸附。

現(xiàn)在不要把這與吸收混淆，物質(zhì)被吸收到細(xì)胞中，進(jìn)入細(xì)胞內(nèi)部。我的意思是，這也發(fā)生在這里，但吸附意味著結(jié)合到細(xì)胞的外表面。絲狀真菌可以吸附有毒重金屬……將它們結(jié)合到其巨大絲狀網(wǎng)絡(luò)的表面，從而為大型土壤生態(tài)系統(tǒng)解毒。重金屬仍然存在，但大量的這些金屬可能會(huì)與幾丁質(zhì)結(jié)合……與土壤中絲狀真菌的細(xì)胞壁結(jié)合……從而在長(zhǎng)達(dá)30年的時(shí)間內(nèi)保持化學(xué)活性，甚至更長(zhǎng)時(shí)間，而不是滲入水系統(tǒng)并污染地下水。

事實(shí)上，我們實(shí)際上可以使用絲狀真菌的細(xì)胞壁作為過(guò)濾器，即使在真菌死亡之后。

例如，制藥工業(yè)在實(shí)驗(yàn)室大量種植絲狀真菌。例如，為了生產(chǎn)抗生素青霉素，制藥公司種植真菌青霉。提取青霉素后，這些死青霉絲……我們可以利用其細(xì)胞壁中的幾丁質(zhì)制造工業(yè)過(guò)濾器來(lái)吸附重金屬。我們可以將這些過(guò)濾器放入工業(yè)過(guò)程中的廢水管道中，并使用這些過(guò)濾器來(lái)捕集汞和鋅等重金屬。之后，我們可以用化學(xué)方法提取重金屬并反復(fù)使用過(guò)濾器。

現(xiàn)在，回到真菌體內(nèi)對(duì)有毒金屬的吸收，讓我們把注意力轉(zhuǎn)向蘑菇。

與其他真菌一樣，蘑菇可以吸收大量重金屬。事實(shí)上，它們所含的有毒金屬濃度可能是它們生長(zhǎng)的土壤中有毒金屬濃度的兩倍半。所以蘑菇，至少是我們?cè)诘孛嫔峡吹降摹覀兛梢詽撛诘厥斋@它們，然后一勞永逸地安全處理其中所含的污染物。

事實(shí)上，為了永久性地清理……尤其是地下水系統(tǒng)……收獲蘑菇可能是最好的方式。據(jù)我所知，出于某種原因，這種情況尚未發(fā)生。但我可以很容易地想象，培養(yǎng)蘑菇的唯一目的是為大型地下生態(tài)系統(tǒng)排毒。

三、Fungi托福聽(tīng)力問(wèn)題：

Q1:1.What is the lecture mainly about?

A.Why fungi cannot grow well in polluted ecosystems

B.Why fungi pose a danger to the underground water system

C.How to prevent heavy metals from getting into the soil

D.How fungi can clean up pollution that is in the soil

Q2:2.What does the professor say about the way fungi get their food?

A.They use certain metal compounds in the soil as nutrients.

B.The enzymes that they produce allow them to absorb organic nutrients from the soil.

C.They separate nutrients from heavy metals and then return the metals to the soil.

D.Heavy metals interfere with their way of getting nutrients from the soil.

Q3:3.What two points does the professor make about chitin?[Click on 2 answers.]

A.Chitin binds strongly to certain heavy metals.

B.Insects need chitin in order to digest the fungi they eat.

C.Chitin can be added to soil to create a good habitat for fungi.

D.The cell walls of fungi,like the exoskeletons of insects,contain chitin.

Q4:4.What do adsorption and absorption in fungi have in common?

A.They both can help the production of new filaments.

B.They both can increase the production of chitin.

C.They both can help keep pollutants out of groundwater.

D.They both result in the strengthening of cell walls.

Q5:5.Why does the professor mention the antibiotic penicillin?

A.To suggest that more fungi should be investigated as potential sources of medications

B.To point out that certain heavy metals are needed for the production of penicillin

C.To criticize the pharmaceutical industry for contributing to environmental pollution

D.To show how a waste product from one process can be useful in another process

Q6:6.Replay:Why does the professor say this:For some reason,this hasn't happened yet as far as I know,but I can easily envision cultivating mushrooms for the sole purpose of detoxifying a large underground ecosystem？

A.She does not have time to fully explain the reason.

B.She is hopeful that students will be able to figure out the reason.

C.She wonders why mushrooms are not already used for cleaning up pollution.

D.She realizes that the research she has been discussing is still in its early stages.

四、Fungi托福聽(tīng)力答案：

A1:正確答案：D

A2:正確答案：B

A3:正確答案：AD

A4:正確答案：C

A5:正確答案：D

A6:正確答案：C

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