问题 单项选择题 A型题

在神经-肌接头的终板膜上,实现跨膜信号转导的方式是()

A.受体-G蛋白-AC途径

B.受体-G蛋白-PLC途径

C.离子通道受体途径

D.酪氨酸激酶受体途径

答案

参考答案:C

解析:

本题考点:细胞信号转导方式。细胞信号转导方式共包括:①离子通道型受体介导的信号转导。②G蛋白偶联受体介导的信号转导。③酶联型受体介导的信号转导三大类型。其中G蛋白偶联受体介导的信号转导又包括受体-G蛋白-AC途径和受体-G蛋白-PLC途径两类;酶联型受体介导的信号转导则包括酪氨酸激酶受体和酪氨酸激酶结合型受体、鸟苷酸环化酶受体两类。神经-肌接头终板膜上,是通过乙酰胆碱激活乙酰胆碱门控的Na+通道导致大量Na+内流,引起终板膜电位升高,诱发动作电位,因此属于离子通道受体介导的信号转导。

阅读理解

Two travelling angels stopped to spend the night in the home of a wealthy family. The family was impolite and refused to let the angels stay in the guest room. Instead the angels were given a space in the cold underground room. As they made their bed on the hard floor, the older angel saw a hole in the wall and repaired it. When the younger angel asked why, the older angel replied, "Things aren't always what they seem."

The next night the pair came to rest at the house of a very poor, but very kind farmer and his wife. After sharing what little food they had, the couple let the angels sleep in their bed where they could have a good night's rest. When the sun came up the next morning, the angels found the farmer and his wife in tears. Their only cow, whose milk had been their only income, lay dead in the field.

The younger angel was very angry and asked the older angel, "How could this happen? Why did you not watch out for the cow? The first man had everything, yet you watched over his house," she accused. "The second family had little but was willing to share everything, and you did not help."

"Things aren't always what they seem," the older angel replied. "When we stayed in the underground room , I noticed there was gold stored in that hole in the wall. Since the owner was so greedy and unwilling to share his good fortune, I asked God if I could seal the wall so he couldn't find it. Then last night as we slept in the farmer's bed, the angel of death came for his wife. I asked God if the angel could take the cow instead. You see, things aren't always what they seem. "

小题1:Why did the older angel repair the hole for the rich family?

A.Because she didn't like the greedy owner.

B.Because she wanted to save the gold for the poor.

C.Because the underground room was too cold to stay in.

D.Because she believed that one should always be ready to offer help.小题2:The younger angel was very angry because ________.

A.the older angel killed the farmer's cow

B.the older angel treated the two families differently

C.the wealthy man gave them a bad place to live in

D.the angel of death took the cow away小题3:Why did the older angel let the farmer's cow die?

A.Because God wanted the older angel to take the cow.

B.Because she wanted to teach the younger angel a lesson.

C.Because she wanted to save the farmer's wife.

D.Because she was sympathetic to the rich.小题4:The story tries to tell readers that ________.

A.angels are always ready to help the poor

B.sometimes things are not what they seem

C.angels are always ready to help the rich

D.the young should always learn from the old

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