问题 解答题

下面是一个健康人的血浆、原尿、尿液的样品,请根据表中的数据回答:

物质样品A(克/100mL)样品B(克/100mL)样品C(克/100mL)
葡萄糖0.00.10.1
无机盐1.60.750.9
蛋白质0.0微量7左右
尿素2.00.030.03
尿酸0.050.0030.003
(1)血浆的样品是______,理由是______.

(2)原尿的样品是______,理由是______.

(3)尿液的样品是______,理由是______.

答案

血浆中含有水、葡萄糖、无机盐、蛋白质、尿素等成分,血液流经肾小球时,其中的水、葡萄糖、无机盐、尿素经过肾小球和肾小囊内壁进入到肾小囊腔中成为原尿,原尿流经肾小管时,大部分的水、一部分无机盐和全部的葡萄糖会被重吸收,剩余的成分,成为尿液.经过两个过程,也造成各成分浓度的变化.

(1)C中既有蛋白质、葡萄糖,又含有无机盐和尿素,为尿液.

(2)B中有葡萄糖、无机盐和尿素,无大分子的蛋白质,为原尿.

(3)A中有无机盐、尿素,没有葡萄糖和蛋白质,血浆.

故答案为:(1)C;血浆中既有蛋白质、葡萄糖,又含有无机盐和尿素

(2)B;原尿中有葡萄糖、无机盐和尿素

(3)A;尿液中有无机盐、尿素,没有葡萄糖和蛋白质

选择题
单项选择题

It is no longer just dirty blue-collar jobs in manufacturing that are being sucked offshore but also white-collar service jobs, which used to be considered safe from foreign competition. Telecoms charges have tumbled, allowing workers in far-flung locations to be connected cheaply to customers in the developed world. This has made it possible to offshore services that were once non-tradable. Morgan Stanley’s Mr. Roach has been drawing attention to the fact that the "global labour arbitrage" is moving rapidly to the better kinds of jobs. It is no longer just basic data processing and call centres that are being outsourced to low-wage countries, but also software programming, medical diagnostics, engineering design, law, accounting, finance and business consulting. These can now be delivered electronically from anywhere in the world, exposing skilled white-collar workers to greater competition.
The standard retort to such arguments is that outsourcing abroad is too small to matter much. So far fewer than lm American service-sector jobs have been lost to off-shoring. Forrester Research forecasts that by 2015 a total of 3.4m jobs in services will have moved abroad, but that is tiny compared with the 30m jobs destroyed and created in America every year. The trouble is that such studies allow only for the sorts of jobs that are already being off-shored, when in reality the proportion of jobs that can be moved will rise as IT advances and education improves in emerging economies.

Which of the following statements is the typical reply concerning off-shoring
[A] Service-sector has sustained a great loss.
[B] White-collar workers will not have a narrow escape.
[C] Most economists underestimated the effects of off-shoring.
[D] Outsourcing abroad has no significant impact.


Alan Blinder, an economist at Princeton University, believes that most economists are underestimating the disruptive effects of off-shoring, and that in future two to three times as many service jobs will be susceptible to off-shoring as in manufacturing. This would imply that at least 30% of all jobs might be at risk. In practice the number of jobs off-shored to China or India is likely to remain fairly modest. Even so, the mere threat that they could be shifted will depress wages.
Moreover, says Mr. Blinder, education offers no protection. Highly skilled accountants, radiologists or computer programmers now have to compete with electronically delivered competition from abroad, whereas humble taxi drivers, janitors and crane operators remain safe from off-shoring. This may help to explain why the real median wage of American graduates has fallen by 6% since 9000, a bigger decline than in average wages.
In the 1980s and early 1990s, the pay gap between low-paid, low-skilled workers and high-paid, high-skilled Workers widened significantly. But since then, according to a study by David Autor, Lawrence Katz and Melissa Kearney, in America, Britain and Germany workers at the bottom as well as at the top have done better than those in the middle-income group. Office cleaning cannot be done by workers in India. It is the easily standardised skilled jobs in the middle, such as accounting, that are now being squeezed hardest. A study by Bradford Jensen and Lori Kletzer, at the Institute for International Economics in Washington D. C., confirms that workers in tradable services that are exposed to foreign competition tend to be more skilled than workers in non-tradable services and tradable manufacturing industries.