Question:
The structural gene lac A in the Lac operon is responsible for
The structural gene lac A in the Lac operon is responsible for
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lac operon:
- lacZ → breakdown
- lacY → transport
- lacA → detoxification
Updated On: May 13, 2026
- prevent entry of glucose into the bacterial cell
- conversion of disaccharide sugar into their monosaccharides
- conversion of lactose into allactose
- removal of toxic byproducts of lactose digestion
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The Correct Option is D
Solution and Explanation
Concept:
The lac operon consists of three structural genes:
• lac Z → $\beta$-galactosidase (breaks lactose into glucose & galactose)
• lac Y → permease (helps lactose enter cell)
• lac A → transacetylase
Step 1: Function of lac A.
• Encodes transacetylase enzyme
• Involved in detoxification
• Removes toxic byproducts formed during lactose metabolism
Step 2: Analyze other options.
• (A) Incorrect → unrelated to lac operon
• (B) lac Z function
• (C) lac Z function (allolactose formation)
• (D) Correct → lac A function
Step 3: Final conclusion.
Thus, lac A is responsible for: \[ Removal of toxic byproducts of lactose digestion \]
• lac Z → $\beta$-galactosidase (breaks lactose into glucose & galactose)
• lac Y → permease (helps lactose enter cell)
• lac A → transacetylase
Step 1: Function of lac A.
• Encodes transacetylase enzyme
• Involved in detoxification
• Removes toxic byproducts formed during lactose metabolism
Step 2: Analyze other options.
• (A) Incorrect → unrelated to lac operon
• (B) lac Z function
• (C) lac Z function (allolactose formation)
• (D) Correct → lac A function
Step 3: Final conclusion.
Thus, lac A is responsible for: \[ Removal of toxic byproducts of lactose digestion \]
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