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【单选题】
（）不是721型分光光度计的组成部件。A.
晶体管稳压电源
B.
玻璃棱镜单色器
C.
10伏7.5安钨丝激励光源
D.
数字显示器
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反馈参考答案：
举一反三
【多选题】How can DNA damage temporarily halt progression through G 1 ?
A.
The cell-cycle control system uses several distinct mechanisms to halt progress through the cell cycle if DNA is damaged, and it can do so at various transition points. The mechanism that operates at the G 1 -to-S transition, which prevents the cell from replicating damaged DNA, is especially well understood.
B.
DNA damage in G 1 causes an increase in both the concentration and activity of a protein called p53, which is a transcription regulator that activates the gene encoding a Cdk inhibitor protein called p21. The p21 protein binds to G 1 /S-Cdk and S-Cdk, preventing them from driving the cell into S phase.
C.
The arrest of the cell cycle in G 1 gives the cell time to repair the damaged DNA before replicating it. If the DNA damage is too severe to be repaired, p53 can induce the cell to kill itself through apoptosis, a form of programmed cell death.
D.
If p53 is missing or defective, the unrestrained replication of damaged DNA leads to a high rate of mutation and the generation of cells that tend to become cancerous. In fact, mutations in the p53 gene are found in about half of all human cancers.
【简答题】Dear Not with the Band, Sometimes friends ____ _____ when one person discovers new interests. But don't ____ __. You could talk to John. Tell him why you're worried and that you'll be there for him if...
【单选题】Induced expenditure includes ( ).
A.
induced consumption and government expenditure
B.
induced consumption expenditure and imports
C.
all autonomous expenditure
D.
induced consumption expenditure and exports
【单选题】The most common type of DNA damage repair is
A.
excision repair.
B.
photoreactivation.
C.
suicide enzyme repair.
D.
DNA photolyase.
E.
proofreading repair.
【简答题】中--英 有时,一个人有了新爱好会和朋友渐渐疏远。
【单选题】Overdose/long-term treatment induced actions which damage function of body is
A.
toxic reaction
B.
side reaction
C.
Secondary reaction
D.
Idiosyncrasy
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