题干

下列关于人体细胞结构和功能的叙述,正确的是(  )

A:有的核糖体附着高尔基体上,是分泌蛋白的合成场所

B:细胞中能产生H和ATP的细胞器有细胞质基质和线粒体

C:可能发生碱基配对的场所有线粒体、核糖体、细胞核等

D:细胞以主动运输的方式吸收葡萄糖

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答案(点此获取答案解析)

C

同类题3

生长素和乙烯与植物生长发育密切相关,请阅读相关资料,回答下列问题:

(1)生长素(IAA)和乙烯作为信号分子,都要通过与受体结合,将信息传递给靶细胞,从而对植物的生命活动起____ 作用.IAA在植物根尖的运输方向是从____ 区到____ 区从而使根伸长.

(2)1964年,科学家进行离体实验发现,当在反应体系中加入14C﹣蛋氨酸,发现有14C﹣乙烯产生,由此推测____ .在以上实验结果的基础上,1979年,美籍华人杨祥发发现,在无氧条件下,当供给植物14C﹣蛋氨酸时,检测不到乙烯产生,只有14C标记的1﹣氨基环丙烷﹣1﹣羧酸(ACC)累积,据此结果推测____ .为了证实上述假设,科学家在____ 条件下,将14C﹣ACC供给植物组织时,发现组织很快____ ,证明上述假设正确.

(3)为研究生长素(IAA)和乙烯影响植物根生长的机理,研究者以拟南芥幼苗为材料进行实验.

①实验一:研究者将拟南芥幼苗放在含不同浓度的ACC、IAA的培养液中培养,测量并记录幼苗根伸长区细胞长度,结果如下表.

组别

添加物质种类及处理浓度(µM)

根伸长区细胞长度(µm)

1

对照

175.1

2

0.20ACC

108.1

3

0.05IAA

91.1

4

0.20ACC+0.05IAA

44.2

实验结果说明,与单独处理相比较,乙烯和IAA对幼苗根伸长区共同作用时____ 

②实验二:将拟南芥幼苗分别放在含有不同浓度IAA的培养液中培养,12小时后测定幼苗根中乙烯的含量,实验结果如图所示.据图分析,可得出的初步结论是____ .

③综合上述各实验的结果可推测,高浓度生长素抑制根生长的作用最可能是通过____ 而实现的.

同类题5

阅读理解

    In the eyes of many foreigners, Chinese are the best hosts (主人) and the worst guests in the world. They're not really bad guests, but because the guest-host relationship in China is much different than in some western counties, it appears they are not nice guests. And western guests sometimes look rude (粗鲁的) in the eyes of Chinese guests.

    In China, guests are almost like gods. Whenever I enter a Chinese person's home, there is always fruit on the table for me, and someone is quick to bring me a cup of tea or water. In the west, generally the guest is not a god. Acting according to the host's way of doing things is usual behavior for a guest.

    My wife's mother, a very kind elderly Chinese lady, doesn't smoke. When I see some of her guests smoking in her house, as a non-smoker, I feel unhappy. Usually I want to stop them directly, but I must realize that in China, to be a good host, she must not do that. In most North America homes, if you are a guest, and the hosts are not smokers, you should not smoke in their house. At the very least, you could ask, “Is it OK if I smoke?” “But, don't be surprised if they say, “No, you can't smoke.” In our culture, if you smoke in their home, you are a bad guest, but if they don't allow you to smoke in their house, they are not a rude guest.

    Guests in China also have special habits. Some western people may not adapt to these habits very soon. Thankfully my wife is Chinese, so whenever we visit a Chinese family she tells me to buy them a gift. However, giving a gift to a host is not always necessary in my country. So, if you invite international guests to your home, don't be too surprised if they don't bring you a gift.

    In China, you probably won't need to change the guest-host relationship very much because you will probably only be the host, and Chinese are naturally very good hosts. If western hosts invite you to their house, try not to be too surprised if their style of treating you is not what you have expected.