【单选题】混凝土的砂率越大,则混凝土的流动性越( )。
【单选题】混凝土的砂率越大,则混凝土的流动性越( )
【单选题】Which of the following statements is false with respectto an enzyme's ability to catalyse a reaction?
A.
An enzyme provides a reaction surface and a suitable environment for the reaction to take place.
B.
An enzyme binds reactants such that they are positioned correctly and can attain their transition-st
C.
An enzyme allows the reaction to go through a less stable transition state than would normally be th
D.
An enzyme can weaken bonds in reactants through the binding process.
【单选题】Which of the following statements about enzyme-linked receptor is false ?
A.
An enzyme-linked receptor is a transmembrane domain receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.
B.
A enzyme-linked receptor has an extracellular ligand-binding domain, a transmembrane domain, and an intracellular catalytic (enzyme) domain.
C.
The signal transduction pathways of enzyme-linked receptor involve phosphorylation cascades.
D.
Enzyme-linked receptor interacts with an intracellular protein called a "G-protein".
【单选题】混凝土的砂率越大,则混凝土的流动性越( )
【单选题】Which statement about enzyme-catalyzed reactions is FALSE?
A.
At saturating levels of substrate, the rate of an enzyme-catalyzed reaction is proportional to the enzyme concentration.
B.
If enough substrate is added, the normal V max of a reaction can be attained even in the presence of a competitive inhibitor.
C.
The rate of a reaction decreases steadily with time as substrate is depleted.
D.
The activation energy for the catalyzed reaction is the same as for the uncatalyzed reaction, but the equilibrium constant is more favorable in the enzyme-catalyzed reaction.
E.
The Michaelis-Menten constant K m equals the [S] at which V = 1/2 V max .
【单选题】混凝土的砂率越大,则混凝土的流动性越( )。
【单选题】Which of the following statements is incorrect regarding Enzyme induction
A.
Enzyme induction induces P450 expression by enhancing the rate of its synthesis
B.
Enzyme induction induces P450 expression by reducing its rate of degradation
C.
Enzyme induction usually results in a decrease in the pharmacologic action of the inducer and also of co-administered drugs
D.
Enzyme induction cannot exacerbate metabolite-mediated toxicity
E.
Environmental chemicals and pollutants are also capable of inducing P450 enzymes
【单选题】Which statement is correct about enzyme ?
A.
All the proteins have the enzymatic activity
B.
It always needs specific cofactor to be activated
C.
Enzyme display enormous catalytic power
D.
It has the absolute specificity to recognize the substrate
【单选题】混凝土的砂率越大,则混凝土的流动性越( ).