Question

【題目】Bacterial Quorum Sensing

Bacteria(細(xì)菌)play an important role in our lives. They can keep us alive as well as make us sick. It wasn’t until fairly recently that we learned bacteria can communicate with one another.

In the 1960s, researchers found that a kind of bacteria called Vibrio fischeri（費(fèi)氏弧菌） produced no light when they were alone, but that they exhibited great amount of light as the bacterial population grew to a certain number. How did this happen? How can Vibrio fischeri tell the difference between times when they’re alone and times when they’re in a community, and then all do something together?

Researchers found they talk to each other with a chemical language—signal molecules(信號(hào)分子). Vibrio fischeri makes signal molecules, and it also has a receptor on its surface that fits like a lock and key with a signal molecule. As the bacteria increase, more and more signal molecules are sent into the environment. When signal molecules increase to a certain amount, they lock down into those receptors and information comes into the bacteria, which tells them how many neighbors there are. As soon as they realize the population has hit the certain number, all of the bacteria behave as a group, making light together. In the past ten years, researchers have found all bacteria have systems like this: they make and recognize chemical words, determine(判斷)the size of the community, and carry out tasks that would be unsuccessful if a single one were to act alone. This process is called quorum sensing.

Most of the time, bacteria live with thousands of other species (種類(lèi))of bacteria. There has to be a language of interspecies communication. In fact, bacteria have another kind of signal molecule, which is the common language used by all species. Moreover, this kind of molecule has its own receptor. In this way, bacteria are able to count different populations, and then they decide what task to carry out depending on which species has the greatest population.

Knowing how bacteria communicate could influence how we fight disease. What if bacteria can’t talk or hear? They won’t recognize when there are enough bacteria and when to exhibit the group behavior to make us sick. Researchers are developing a method—to make molecules that look like the real ones and then they lock into the receptors to jam recognition of the real situation.

On the other hand, researchers also improve the conversation of the beneficial bacteria, so they can do things that we want them to do better than they would do on their own.

【1】According to the passage, what can we learn about quorum sensing?

A.Quorum sensing may happen when there is only one Vibrio fischeri.

B.Signal molecules are kept away from receptors during quorum sensing.

C.Most bacteria have similar systems to make light during quorum sensing.

D.Bacteria carry out a group task when their population hit a certain number.

【2】What can we learn from the passage?

A.The more species there are, the more group actions bacteria will take.

B.In different environments, bacteria have different interspecies languages.

C.Beneficial bacteria communicate better by themselves than harmful ones.

D.To fight disease, researchers try to turn off the communication between harmful bacteria.

【3】The passage is mainly about ________.

A.why bacterial population growsB.how bacteria communicate with each other

C.which bacteria help fight diseaseD.what scientists do to find quorum sensing

Answer 1

【答案】

【1】D

【2】D

【3】B

【解析】

本文向我們介紹了細(xì)菌群體感應(yīng)機(jī)制，告訴我們細(xì)菌是如何相互交流的。

【1】

細(xì)節(jié)理解題。根據(jù)第二段中“As soon as they realize the population has hit the certain number, all of the bacteria behave as a group…if a single one were to act alone. This process is called quorum sensing.”可知，一旦發(fā)現(xiàn)細(xì)菌數(shù)量達(dá)到一定數(shù)量，所有的細(xì)菌就會(huì)一起發(fā)光。研究人員發(fā)現(xiàn)所有的細(xì)菌都有這樣的系統(tǒng)，判斷群體的大小，并且如果單獨(dú)行動(dòng)的話執(zhí)行的任務(wù)將會(huì)失敗。這個(gè)過(guò)程稱(chēng)為群體感應(yīng)。結(jié)合選項(xiàng)，故選D。

【2】

推理判斷題。根據(jù)第四段中“Researchers are developing a method—to make molecules that look like the real ones and then they lock into the receptors to jam recognition of the real situation.”可知，研究人員正在開(kāi)發(fā)一種方法——使分子看起來(lái)像真實(shí)的分子，然后它們鎖定在受體上，阻礙對(duì)真實(shí)情況的識(shí)別。所以為了對(duì)抗疾病，研究人員試圖關(guān)閉有害細(xì)菌之間的交流。故選D。

【3】

主旨大意題。A：細(xì)菌種群為什么會(huì)增長(zhǎng)；B：細(xì)菌是如何相互交流的；C：哪些細(xì)菌有助于對(duì)抗疾病；D：科學(xué)家如何發(fā)現(xiàn)群體感應(yīng)。分析全文內(nèi)容可知，本文向我們介紹了細(xì)菌群體感應(yīng)機(jī)制，告訴我們細(xì)菌是如何相互交流的。故選B。