阻遏物（Repressor）

TrpR Repressor与Lac Repressor一样都是与诱导物(inducer)结合后不能结合到操纵基因(operator)上。_

Operator: ( ) A: An operator is a DNA region that is working with promoter for genes to express. B: An operator is a DNA region at 5’ of a gene for a repressor to bind to prevent gene expression. C: An operator is a repressor protein to help genes to express. D: An operator is a repressor protein to inhibit genes to express.

与分解代谢相关的操纵子中，存在分解代谢抑制现象，参与这一调控的主要作用因子是（ ）? CRP-cAMP|LacI repressor|Attenuator|TrpR repressor

Operator is bound by A: activator B: repressor C: promoter D: enhancer E: silencer

The operator is A: Another name for the terminator of a gene B: A DNA site bound by repressor proteins C: A protein that coordinates gene expression D: A part in the leader region of mRNA

Operator is() A: where the<br/>repressor binds to regulate gene expression in an operon. B: controlled<br/>by promoter. C: is induced<br/>by lactose. D: is repressed<br/>by tryptophan.

When only glucose is available to E. coli in the culture medium:  ( ) A: cAMP-CAP is bound to the promoter； B: cAMP-CAP is not bound to the promoter； C: The repressor is not bound to the operator； D: The lac operon is turn on 

在真核基因表达调控中，( )调控元件能促进转录的速率。 A: 弱化子 B: 增强子 C: repressor D: TATA Box

在真核基因表达调控中，( )调控元件能促进转录的速率。 A: 衰减子 B: 增强子 C: repressor D: TATA Box