问题 解答题

根据米勒的实验结果,可以推测生命的起源经历了从无机物到形成有机物的过程.______.

答案

米勒的实验装置如下图

    生命起源的学说有很多,其中化学起源说是被广大学者普遍接受的生命起源假说.这一假说认为,地球上的生命是在地球温度逐步下降以后,在极其漫长的时间内,由非生命物质经过极其复杂的化学过程,一步一步地演变而成的.化学起源说将生命的起源分为四个阶段:第一个阶段,从无机小分子生成有机小分子的阶段;第二个阶段,从有机小分子物质生成生物大分子物质;第三个阶段,从生物大分子物质组成多分子体系;第四个阶段,有机多分子体系演变为原始生命.米勒通过实验验证了化学起源学说的第一阶段.

    米勒的实验如图,将水注入左下方的烧瓶内,先将玻璃仪器中的空气抽去.然后打开左方的活塞,泵入甲烷、氨和氢气的混合气体(模拟原始大气).再将烧瓶内的水煮沸,使水蒸汽和混合气体同在密闭的玻璃管道内不断循环,并在另一容量为5升的大烧瓶中,经受火花放电(模拟雷鸣闪电)一周,最后生成的有机物,经过冷却后,积聚在仪器底部的溶液(模拟原始大气中生成的有机物被雨水冲淋到原始海洋中).此实验结果共生成20种有机物.其中11种氨基酸中有4种(即甘氨酸、丙氨酸、天冬氨酸和谷氨酸)是生物的蛋白质所含有的.米勒的实验试图向人们证实,生命起源的第一步,即从无机小分子物质形成有机小分子物质,在原始地球的条件下是完全可能实现的.

故答案为:√

选择题
阅读理解

You probably know you should say "please" and "thank you" at restaurants. You probably know the rules of a library. You know you should respect and be nice to your classmates. But do you have music manners?

Keep It Down! You have to notice the volume of your music. You should not play your music so loud that everyone around you can hear it. Some people might even get angry. Usually, when you play the music loud on an MP3 player, other people can't hear the words of the song. They just hear a loud sound. No one wants to listen to this. Very loud music can also be bad for your ears. So even if you are alone when listening to your MP3 players, you shouldn't turn it up too high.

Take Them Off! You need to know when to turn your MP3 off and put it away. Libraries, and schools don't allow MP3 players. There are other places, like museums, that don't have rules, but it would be rude to have your MP3 player on. Sometimes, it doesn't make sense to listen on your MP3 player at event. Why would you listen to music at a play, a movie or a sporting event? You would miss what is going on and others would wonder why you even came.

Take One Out! Once in a while it's okay just to take out one earphone and not the other. Imagine you are listening on your MP3 player when someone asks you the way. It would not be rude to take out one earphone, tell him the way, and put back the earphone and continue listening. You can also do this when you order food at a fast-food restaurant or when you answer the telephone

It's Your Choice! There are times when you need to decide what is best. For example, some people can listen to music on their MP3 players when reading books, while others think it is disturbing. In cases like this, you need to do what seems right for you.

小题1:The underlined word "volume" in Paragraph 2 probably means "_________."

A.the type of music

B.the length of a song

C.the amount of a sound

D.the color of an MP3 player小题2:We should turn down the music when we are alone because loud music_________.

A.may annoy others

B.can hurt our ears

C.is bad for MP3 players

D.will make us tired小题3:If we listen to our MP3 player at a play, _________.

A.the theatre won't allow it

B.the actors will get angry

C.others won't hear the play well

D.we may miss part of the play小题4:We can take one earphone out when we _________.

A.show others the way

B.enjoy a movie at the cinema

C.watch a sporting event

D.answer the telephone at museums 小题5:The main idea of this passage is about _________.

A.MP3 manners

B.music lovers

C.music players

D.MP3 earphones