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问题 单项选择题 A1型题

蛋白质肽链的α-螺旋每上升一圈相当于多少个氨基酸残基（）

A.2个

B.3个

C.3.2个

D.3.6个

E.4.2个

答案

参考答案：D

解析：α-螺旋为蛋白质二级结构，螺旋走向为顺时针方向，每3.6个氨基酸残基螺旋上升一圈，螺距为0.54nm。

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缺词填空

      The USA has a much bigger population （人口）than Australia, and A_1_ cities are m_2_ crowded than Australian o_3_. There are not so many mountains in Australia as in the USA. Both countries have

deserts and beautiful b_4_. But America has many more rivers than Australia. The northern and central

parts of the USA h_5_ much more snow in winter than a_6_ in Australia and generally these two areas

have a colder w_7_ than Australia does. Australia is in the southern hemisphere（半球） and doesn’t

have its winter at the same time a_8_ countries in the northern hemisphere. Most people in these countries s_9_ the same language ---English, but their accents(口音) are very d_10_.
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多项选择题

心理学上把（）等情绪统称为负性情绪，有时又称为负面情绪。 

A.焦虑

B.紧张

C.悲伤

D.愤怒
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