问题 问答题 简答题

简述细胞信号转导的基本过程。

答案

参考答案:

可分为:信号的感知和跨膜转换、胞内信号的传导、细胞的生理生化反应3各阶段。

一、信号感知和跨膜运输:植物细胞感受并接受外界刺激,将保外信号转化为胞内信号。这些依靠细胞表皮完成。

(一)胞外信号的传递:1.化学信号的传递;2.物理信号的传递。

(二)细胞表面受体对信号的感知和转换(物理信号、化学信号):不同细胞表皮受体对信号的感知和转换过程不同

1.由离子通道连接受体跨膜转换信号

2.由酶联受体直接跨膜转换信号

3.由G蛋白偶联受体跨膜转换信号

二、胞内信号的传导:细胞信号转导的主要过程,主要包括细胞内第二信使的产生、蛋白质的可逆磷酸化以及信号的级联放大。

(一)胞内第二信使系统:主要有钙信使系统、环核苷酸信使系统和肌醇磷脂信使系统。

(二)蛋白质的可逆磷酸化:细胞信号传递过程中的共同环节,也是中心环节。

(三)信号的级联放大:通过受体激活G蛋白、产生第二信使、激活相应的蛋白激酶和促使底物蛋白磷酸化等一些列反应得到级联放大

三、细胞的生理生化反应:

(1)细胞代谢(2)细胞分裂(3)细胞分化(4)细胞功能(5)细胞死亡

可分为长期效应和短期效应

答案2(教学网提供):细胞信号传导的途径,可分为四个阶段,即:

(1)胞间信号传递化学信号或物理信号在细胞间的传递。

(2)膜上信号转换把胞间信号转换成胞内信号的过程。

(3)胞内信号转导将胞内信号转换为具有调节生理生化功能的调节因子的过程。

(4)蛋白质可逆磷酸化对靶酶进行磷酸化或去磷酸化的反应,使靶酶执行生理功能

完形填空

下面文章中有5处(第61 – 65题)需要添加小标题。请从以下选项(A、B、C、 D、E 和 F)中选出符合各段意思的小标题,并在答题纸上将相应选项的标号涂黑。选项中有一项是多余选项。

A. Art history provides information of different places and people.

B. Lack of stone images also reflects religious belief.

C. Art is a good means to know about people’s faith.

D. Artists express their feelings and opinions in their works.

E. People know more about our culture through learning art history.

F. Art is by all means relevant to history.

61. ____________________________

A study of art history might be a good way to learn more about a culture than it is possible to learn in general history classes. Most typical history courses concentrate on politics, economics and war. But art history focuses on much more than this because art reflects not only the political values of a people, but also religious beliefs, emotions, and psychology.

62. ____________________________

In addition, information about the daily activities of our ancestors---or of people very different from our own---can be provided by art. In short, art expresses the essential qualities of a time and a place, and a study of it clearly offers us a deeper understanding than what can be found in most history books.

63. ____________________________

In history books, objective information about the political life of a country is presented; that is, facts about politics are given, but opinions are not expressed. Art, on the other hand, is subjective: it reflects emotions and opinions. The great Spanish painter Francisco Goya was perhaps the first truly “political” artist. In his well-known painting The Third of May 1808, he criticized the Spanish government for its misuse of power over people. Over a hundred years later, symbolic images were used in Pablo Picasso’s Guernica to express the horror of war. Meanwhile, on another continent, the powerful paintings of Diego Rivera, Jose Clemente Orozco, and David Alfaro Siqueiros---as well as the works of Alfredo Ramos Martins---depicted(描述)these Mexican artists’ deep anger and sadness about social problems.

64. ____________________________

In the same way, art can reflect a culture’s religious beliefs. For hundreds of years in Europe, religious art was almost the only type of art that existed. Churches and other religious buildings were filled with paintings that depicted people and stories from the Bible. Although most people couldn’t read, they could still understand biblical(圣经的)stories in the pictures on church walls.

65. ____________________________

By contrast, one of the main characteristics of art in the Middle East was (and still is) its absence of human and animal images. This shows the Islamic belief that statues are unholy. Something else can be more religiously symbolic in history.

判断题