sat阅读官方每日一题，又来啦，sat备考生们，大家都准备好了接受这道试题的考验了吗?好啦，废话不多说了，现在，就请众位考生跟随教育小小编的脚步，一起去看看这道sat阅读试题!

　　Critical Reading>Select an Answer

　　Like an opera house, which has its public entranceseparate from that for the performers, a cell hasdifferent doors for different molecules. Each getsscrutinized at its door bore it can enter the cell. Now researchers from the University of California atSan Francisco have revealed in the journal Science the three-dimensional structure of onesuch door, or membrane channel, that specializes in granting entry to a membranecomponent known as glycerol. Specifically the channel is called the glycerol facilitator (GlpF), from the bacterium Escherichia coli.

　　Bearing three alcohol groups, glycerol is a basic building block for the cell membrane. (Other components include fatty acids and small charged molecules.) And not just in E. coli. Indeed, although the channel the researchers studied is from a bacterium, it belongs to alarge protein family dubbed the aquaporins, which are found in species ranging from bacteriato humans.

　　GlpF is highly specific for glycerol and similar polyalcohols. Somehow, even though watermolecules are much smaller, they cannot enter. The new study reveals why. In order forglycerol to clear the four-channel configuration in the cell membrane, it must pass througha narrow selectivity filter in the center of a channel. Here it is surrounded by amino acidsthat closely match its own structure, which is hydrophilic ("water-loving") on one side andhydrophobic ("water-fearing") on the other. Water molecules, in contrast, can only passthrough this area in single file, which is not energetically favorable, because they like to bondto one another. And ions, which are charged, are unable to pass the "water-fearing" side of thechannel. This cell entrance, it seems, is truly exclusive.

　　The main purpose of the passage is to ____

　　A.explain the ways proteins function in various species.

　　B.analyze and argue against a common claim about bacteria.

　　C.assert that a new research technique will enhance future studies in the field of cellularbiology.

　　D.discuss a study that offers a new understanding of a fundamental cellular process.

　　澳际温馨提示：各sat考生在看过上述sat阅读试题之后，自己分析解答，再看相应的sat阅读答案及解析，会更有效哦!

　　答案：D

　　解析：

　　Choice D is the best answer. The author's focus is on discussing work done by researchers studying the structure of membrane channels in cells. According to the author, the researchers' study revealed how certain molecules move through cells' membranes.

　　比答案更重要的是解析，所以，不管上述sat阅读试题是对还是错，都希望sat备考生们能够正视答案解析部分，毕竟这才能助大家一臂之力!好啦，今天的sat阅读资讯，到此结束，如需掌握其他，还请继续关注澳际教育相关培训，谢谢合作!

　　sat金牌一对一

　　想要快速提分，一对一最适合你

　　1一对一会根据你的实际情况制定计划

　　2每天有专职顾问记录你全天的学习进度

　　3授课的时间、地点、形式都非常灵活

　　4一对一授课的吸收率是大班课的5倍

　　5教学更具交流性，课堂上可随时反馈

　　6每学科教师辅导+专门学习顾问+助教

　　数据证明一对一授课的吸收率，是大班课的5倍!

　　澳际标准化sat课程教学体系——平均教龄5年以澳际师研发，历经8年sat考试实战验证，数据证明一对一授课的吸收率，一对一授课效率是小班授课的2~3倍，是大班课的5倍，最大限度保证学习效果，家长要做的就是放心把孩子交给澳际。

　　一对一授课能为你做什么?

　　一对一的授课非常适合想要快速提分的学生，它的吸收率比班课更高，排课更为灵活，这意味着用更短的时间达成目标。尤其是想要冲击高分的学生，很难在约定俗成的班课上有针对性地弥补短板。老师在一对一的形式下，也能更好地照顾到学生的需求。以作文批改为例，如果是班课就难以实现，因为数量太多了，费时费力。但在澳际的一对一授课中，每位学生都能获得经老师2次修改成文的文章4-6篇。想在25分钟内流畅地写出500词以上的文章，没有这个打磨的过程，谈何容易。

　　自由安排上课时间，网络课堂克服地理限制

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