试题与答案

对怀孕的哺乳动物中氧的转运研究显示在同样条件下测量婴儿和母亲的血液氧饱和曲线明显不同

题型:问答题 简答题

题目:

对怀孕的哺乳动物中氧的转运研究显示在同样条件下测量婴儿和母亲的血液氧饱和曲线明显不同。这是因为婴儿的红细胞中含有结构不同的血红蛋白F(a2g2),而母亲的红细胞含有一般的血红蛋白A(a2g2)。

(a)在生理状况下,哪一种血红蛋白对氧有更高的亲和性。请解释。

(b)不同的氧亲和性有何生理意义?)当所有的2,3-二磷酸甘油酸(BPG)从血红蛋白A和F中移去后,测得的氧饱和曲线往左移。不过此时的血红蛋白A比血红蛋白F对氧有更高的亲和性。当加回BPG时,氧饱和曲线又恢愎正常情形。BPG对血红蛋白的氧亲和性有何影响?用以上资料解释婴儿和母亲的血红蛋白的不同氧亲和性?

答案:

参考答案:

(a)当氧分压为4kPa时,HbA只有33%的氧饱和度,而HbF为58%,表明HbF比HbA对氧的亲和性更高。

(b)HbF对氧的高亲和性可确保氧可以由母体血液流向胎盘中的胎儿血液。

(c)当结合BPG时,与HbF相比,HbA氧饱和曲线发生了更大的漂移,表明HbA结合BPG比HbF结合BPG更紧密,而结合BPG就减少了对氧亲和性。

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题型:阅读理解

第三部分:阅读理解(每小题2分,满分40分) 

A

Hello, Listeners. Welcome to Henton Hospital Radio. Before our music programme at four, I’m going to repeat some of our hospital rules.

The hospital can sleep 800 patients. There’re 8 beds in each ward (病房). The visiting hours are in the afternoon from 2:30 to 3:30 and in the evening from 7:00 to 8:00. But remember only two people can see you at the same time. Sorry about that, but you can see what would happen if we didn’t have these rules.

The other rules are about our hours. We start quite early---you might not be used to that. We wake you at 6 o’clock, and breakfast is at 8 o’clock, lunch is at noon.

There’s tea at 3:30 and supper is at 6 o’clock.

You can see the non-smoking sign –-- we don’t allow smoking in the wards. I’m sure you understand why. However, if you do need to smoke, there are some smoking rooms where It is allowed.

You will find the radio switch (开关) on the wall near your bed, with your own headphones, if you want to listen. It’s our own hospital radio wishing you a quick recovery (康复).

56. Who do you think the listeners might be?  

A. Patients.     B. Visitors.    C. Doctors     D. Nurses

57. How many wards are there in this hospital? 

A. 8       B. 80      C. 100      D. 800

58. Which is Not allowed in the hospital?

A. Listening to the hospital radio.               B. Visiting patients in the morning.

C. Smoking in smoking-rooms.               D. Getting up early in the morning.

59. What programme will follow this radio talk?

A. Hospital rules.  B. A weather report.   C. A free talk.     D. A music programme.

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