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प्रश्न
Explain the role of Lactose as an inducer in Lac-operon.
उत्तर
- A few molecules of lactose enter into the cell by an enzyme permease.
- A small amount of this enzyme is present even when the operon is switched off.
- A few molecules of lactose, act as an inducer and bind to the repressor.
- This repressor–inducer complex fails to join with the operator gene, which is then turned on.
- Structural genes produce all enzymes. Thus, lactose acts as an inducer of its own breakdown.
- When the inducer level falls, the operator is blocked again by a repressor. So structural genes are repressed/inactivated again. This is negative feedback.
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संबंधित प्रश्न
A unit of lac-operon which in the absence of lactose, suppresses the activity of operator gene is
Give diagrammatic representation of Lac-operon in the presence of inducer.
With respect to lac- operon explain the following terms:-
- regulator gene
- promoter gene
- structural gene
- inducer
Which of the following is the function of promoter in lactose operon of Escherichia coli?
Identify the INCORRECT statement/s.
- Regulation of lac operon by repressor is referred to as negative regulation.
- The repressor protein produced by regulator gene binds to the operator region.
- The sequence constituting the operator region is present upstream of promoter region
- Each operon bas a specific 'Operator'.
In which of the following conditions the lac operon in E. coli becomes "switched on"?
In Escherichia coli lac Operon is induced by ______.
The wild type E. coli cells are growing in normal medium with glucose. They are transferred to a medium containing only lactose as sugar. Which of the following changes takes place?
During expression of an operon, RNA polymerase binds to ______.
Which of the following cannot act as inducer?
