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【单选题】
一切都可以还原为物理学的是()。A.
物理学主义
B.
唯科学主义
C.
经济学帝国主义
D.
大物理学主义
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反馈参考答案：
举一反三
【单选题】将报表中的某个总体指标作为100%,再计算出各组成项目占该总体指标的百分比,来比较各个项目的百分比的增减变动的财务报表分析的基本方法是( )
A.
比较分析法
B.
趋势分析法
C.
项目质量分析法
D.
结构分析法
【多选题】How do G proteins work?
A.
There are several varieties of G proteins. Each is specific for a particular set of receptors and for a particular set of target enzymes or ion channels in the plasma membrane. All of these G proteins, however, have a similar general structure and operate in a similar way. They are composed of three protein subunits—α, β, and γ—two of which are tethered to the plasma membrane by short lipid tails.
B.
In the unstimulated state, the α subunit has GDP bound to it, and the G protein is idle.
C.
When an extracellular signal molecule binds to its receptor, the altered receptor activates a G protein by causing the α subunit to decrease its affinity for GDP, which is then exchanged for a molecule of GTP. In some cases, this activation breaks up the G-protein subunits, so that the activated α subunit, clutching its GTP, detaches from the βγ complex, which is also activated.
D.
The two activated parts of the G protein—the α subunit and the βγ complex—can then each interact directly with target proteins in the plasma membrane, which in turn may relay the signal to other destinations in the cell. The longer these target proteins remain bound to an α subunit or a βγ complex, the more prolonged the relayed signal will be.
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