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Question
According to the lac-operon concept, which functional unit of the bacterial gene material is responsible for suppressing the activity of the operator gene in the absent of lactose?
According to the lac-operon concept, which functional unit of the bacterial gene material is responsible for suppressing the activity of the operator gene in the absent of lactose?
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Solution
The correct option is C Regulator gene
Lac operon consists of following components:
Structural genes- Theses are lac Z, lac Y and lac A which transcribe polycistronic mRNA and form 3 enzymes- beta galactosidase, lactose permease and transacetylase. Operator gene- They control the functioning of structural genes. The cistrons are expressed only when the operator gene is turned on by an inducer which is lactose. Promoter gene- It marks the site where RNA polymerase binds.Regulator gene- In the absence of lactose, the regulator gene which codes for a protein called repressor combines with operator gene to stop its action. Thus the regulator gene suppresses the activity of operator gene.Thus, the correct answer is option C.
Lac operon consists of following components:
Structural genes- Theses are lac Z, lac Y and lac A which transcribe polycistronic mRNA and form 3 enzymes- beta galactosidase, lactose permease and transacetylase.
Operator gene- They control the functioning of structural genes. The cistrons are expressed only when the operator gene is turned on by an inducer which is lactose.
Promoter gene- It marks the site where RNA polymerase binds.
Regulator gene- In the absence of lactose, the regulator gene which codes for a protein called repressor combines with operator gene to stop its action. Thus the regulator gene suppresses the activity of operator gene.
Thus, the correct answer is option C.
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