Which of the following statements is correct regarding the repressor of the $lac$-operon?

  • A
    It is a tetrameric protein.
  • B
    It has a molecular weight of $16,000$.
  • C
    It has only one binding site.
  • D
    It is synthesized by the regulator gene ($i$-gene).

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Similar Questions

Select two statements out of the four given statements $(i-iv)$ with respect to the $lac$ operon.
$(i)$ Glucose or galactose binds with the repressor and inactivates it.
$(ii)$ In the absence of lactose,the repressor binds with the operator.
$(iii)$ The $Z$-gene codes for permease.
$(iv)$ It was elucidated by Francois Jacob and Jacques Monod.

The diagram below shows a diagrammatic sketch of the maturation of insulin. Select the correct set of names labeled $A, B, C$,and $D$.

Match the following genes of the $Lac$ operon with their respective products.
$(a)\; i$ gene$(i)\; \beta-\text{galactosidase}$
$(b)\; z$ gene$(ii)\; \text{Permease}$
$(c)\; a$ gene$(iii)\; \text{Repressor}$
$(d)\; y$ gene$(iv)\; \text{Transacetylase}$

Select the correct option.

Wild-type $E. coli$ cells are grown in a normal medium containing glucose. They are then transferred to a medium containing only lactose as the sugar source. Which of the following changes will occur?

Consider the following statements of gene regulation and select the correct statements $:$
$(A)$ Expression of genes is regulated by metabolic,physiological,or environmental conditions.
$(B)$ Galactose can act as an inducer for the lac operon.
$(C)$ The operator region is adjacent to the promoter elements in most operons.
$(D)$ In the lac operon,lactose is transported into the cell through the action of permease.
$(E)$ Regulation of the lac operon by a repressor is referred to as positive regulation.

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