People who are known to be lactose intolerant do the lactose digesting enzyme, lactase . This happens because the lactase producing gene is shut off in their cells connected to the digestive system . Which of the following process is not occurring for the mentioned gene ?

Options

A. Translation
B. Mutation
C. Replication
D. Transcription

Answer

To solve the question regarding lactose intolerance and the lactase enzyme, we need to analyze the processes involved in gene expression and identify which one is not occurring for the lactase-producing gene in lactose intolerant individuals.

### Step-by-Step Solution:

1. **Understanding Lactose Intolerance**:
- Lactose intolerance occurs when individuals cannot digest lactose, a sugar found in milk, due to a lack of the enzyme lactase.

2. **Role of the Lactase Gene**:
- The lactase enzyme is produced from the lactase gene. In lactose intolerant individuals, this gene is present but is "shut off," meaning it is not actively producing the enzyme.

3. **Gene Expression Process**:
- Gene expression involves several key steps:
- **Transcription**: The DNA sequence of a gene is transcribed to produce messenger RNA (mRNA).
- **Translation**: The mRNA is then translated into a protein (in this case, the lactase enzyme).

4. **Identifying the Problem**:
- Since the lactase gene is "shut off," it means that the transcription of the gene into mRNA is not occurring. If transcription does not happen, then translation cannot occur, and thus the enzyme lactase is not produced.

5. **Analyzing the Options**:
- The question asks which process is not occurring for the lactase gene. Given the information:
- **Transcription** is not happening because the gene is shut off.
- **Translation** cannot occur without transcription, but it is not the primary process that is shut off.
- **Replication** of the gene is still happening, as the gene is present in the DNA.
- **Mutation** is not relevant here as there is no defect in the gene itself; it is simply not being expressed.

6. **Conclusion**:
- The process that is not occurring for the lactase-producing gene in lactose intolerant individuals is **Transcription**.

### Final Answer:
**Transcription is not occurring for the lactase-producing gene in lactose intolerant individuals.**

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