调节子是指 A.操纵子 B.一种特殊蛋白质 C.成群的操纵子组成的调控网络 D.mR

题型:单项选择题

问题:

调节子是指

A.操纵子
B.一种特殊蛋白质
C.成群的操纵子组成的调控网络
D.mRNA的特殊序列
E.调节基因

考点:临床执业医师生物化学基因表达调控
题型:单项选择题

现有一种烃,可表示为

命名此化合物时,应该认定的主链上的碳原子数目是(  )

A.8

B.9

C.10

D.11

题型:单项选择题

如图所示,一个横截面为直角三角形的三棱镜,∠A=30°,∠C=90°,BC边的长为L.一个大光屏MN与BC平行,到BC的距离也是L.三棱镜材料的折射率是n=

3
.一束平行光平行于AC方向射到三棱镜的 AB面上.求:

(1)用作图法画出光屏上被照亮的部分,并求被照亮部分的宽度.

(2)光屏移动到什么位置才能消除两个照亮部分之间的阴影区?

题型:单项选择题

《关于进一步加强和改进新形势下高校宣传思想工作的意见》,《意见》中指出意识形态工作是党和国家一项极端重要的工作,高校作为意识形态工作前沿阵地。高校为什么是意识形态工作的前沿阵地?

题型:单项选择题

患者男性,50岁,机械性肠梗阻人院,出现最早和最主要的病理生理改变是

A.感染

B.中毒

C.体液紊乱

D.呼吸困难

E.心功能不全

题型:单项选择题

Studies from 10 nations reveal that the rates of depression among women are twice as high as they are among men. Do women have a biological bent for depression, or are social double standards the major cause

Mental health workers have long noticed among the clinically depressed women take up a bigger proportion. Until recently, though, it was unclear whether more women than men were ill or, instead, whether more women sought help. In fact, a mounting collection of studies has confirmed that major depression is twice as common among women as it is among men. "This is one of the most consistent findings we have ever had," says Myrna M. Weissman of Columbia University.

Scientists searching for explanations are challenged by the fact that a variety of cues prompt depression in different people. Sorting out which factors might have a greater influence on women has not proved easy. Both sexes stand an equal chance of inheriting major depression, so genes are most likely not to blame. Yet hormones and sleep cycles--which differ dramatically between the sexescan alter mood. Also, many workers have proposed that social discrimination might put women under high levels of stress.

In 1990 an international group examines mood disorders. In the 10 nations reviewed so far, the team has found that among generations reaching maturity after 1945, depression seems to be on the rise and occurs at a younger age. Although overall incidence varies regionally, "everywhere the rates of depression among women are about twice as high as they are among men," Weissman says.

In contrast, lifetime rates for manic-depressive illness do not differ according to sex or culture. Mark S. George and his colleagues at the National Institute of Mental Health (NIMH) recently studied which regions of the brain have greater blood flow during periods of depression. George found that "the brain activity of the men and women of depression looked very different. " He has since compared feelings of anger, anxiety and happiness, finding no such big a difference.

Because one in five American women has a history of depression, especially as they often pursue therapy from other sources, sometimes on top of an anti-depressant clinic. Says Leibenluft: "It is remarkable how little work has been done on this subject.

The author quotes Leibenluft’s comment in the last paragraph to()

A. summarize the main idea of the passage

B. recommend an alternative perspective to look at the issue of depression

C. express the author’s pity about the slow improvement on the cure of depression

D. praise the great efforts made by researchers on the subject of depression

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