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【简答题】
After graduation, I came to realize ____________ (我多么感激我的老师).
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举一反三
【单选题】The pathway by which the parasites travel from one host to another is called the route of___.
A.
sterilization
B.
disinfection
C.
transmission
【简答题】过程工业是以( )为处理对象,完成各种生产过 程的工业。通常由一系列的( )和 ( ) ,按一定的流程方式用管道、阀门等连接起来的一个独立的密闭连续系统,再配以必要的控制仪表和设备,来完成产品的生产过程。
【单选题】The statins are the major class of medications used to lower elevated serum cholesterol by initially inhibiting the major rate-limiting step of cholesterol synthesis. Which metabolite of the pathway w...
A.
Acetoacetyl-CoA
B.
HMG-CoA
C.
Mevalonate
D.
Squalene
E.
Steroid ring
【简答题】A.Two thousand feet. B.Twelve thousand feet. C.Twenty thousand feet. D.Twenty-two thousand feet.
【单选题】In order for a cell to carry out its biologic functions, the intracellular reactions need to be directed to follow a certain pathway. Which one statement best describes the direction a chemical reacti...
A.
A reaction with positive free energy will proceed in the forward direction if the substrate concentration is raised high enough.
B.
Under standard conditions, a reaction will proceed in the forward direction if the free energy Δ G0 ′ is positive.
C.
The direction of a reaction is independent of the initial substrate and product concentrations because the direction is determined by the change in free energy.
D.
The concentration of all of the substrates must be higher than that of all of the products for the reaction to proceed in the forward direction.
E.
The enzyme for the reaction must be working at >50% of its maximum efficiency for the reaction to proceed in the forward direction.
【单选题】Which of the following tissue synthesize purine nucleotides mainly by salvage pathway
A.
bone marrow
B.
liver
C.
kidney
D.
myocardium
E.
skeletal muscle
【多选题】What are the pathway of transcription initiation and the fate of the σ subunit in bacteria?
A.
The pathway consists of two major parts, binding and initiation, each with multiple steps. First, the polymerase, directed by its bound σ factor, binds to the promoter. A closed complex (in which the bound DNA is intact) and an open complex (in which the bound DNA is intact but partially unwound near the −10 sequence) form in succession.
B.
Second, transcription is initiated within the complex, leading to a conformational change that converts the complex to the elongation form, followed by movement of the transcription complex away from the promoter (promoter clearance).
C.
Any of these steps can be affected by the specific makeup of the promoter sequences. The σ subunit dissociates stochastically (at random) as the polymerase enters the elongation phase of transcription. The protein NusA (Mr 54,430) binds to the elongating RNA polymerase, competitively with the σ subunit.
D.
Once transcription is complete, NusA dissociates from the enzyme, the RNA polymerase dissociates from the DNA, and a σ factor (σ 70 or another) can again bind to the enzyme to initiate transcription.
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