Which of the following is produced by E-Coli in the lactose operon.

Options

A. B galactosidase
B. Transacetylase
C. Permease
D. All of the above

Answer

To answer the question "Which of the following is produced by E. coli in the lactose operon?", we can break down the process of the lac operon and the products it generates step by step.

### Step-by-Step Solution:

1. **Understanding the Lac Operon Structure**:
- The lac operon consists of several components: a promoter (P), an operator (O), a regulator gene (I), and three structural genes (Z, Y, and A).
- The I gene produces a repressor protein that binds to the operator, preventing transcription of the structural genes when lactose is absent.

2. **Role of Lactose**:
- When lactose is present in the environment, it binds to the repressor protein produced by the I gene.
- This binding causes a conformational change in the repressor, preventing it from binding to the operator.

3. **Activation of Structural Genes**:
- With the repressor no longer bound to the operator, RNA polymerase can bind to the promoter and transcribe the structural genes (Z, Y, and A).
- The structural genes encode specific proteins that are crucial for lactose metabolism.

4. **Products of the Lac Operon**:
- **Gene Z**: Codes for **beta-galactosidase**, an enzyme that breaks down lactose into glucose and galactose.
- **Gene Y**: Codes for **lac permease**, a protein that facilitates the entry of lactose into the bacterial cell.
- **Gene A**: Codes for **transacetylase**, an enzyme that is involved in the metabolism of lactose.

5. **Conclusion**:
- Therefore, the products produced by E. coli in the lactose operon are beta-galactosidase, lac permease, and transacetylase.

### Final Answer:
All of the following are produced by E. coli in the lactose operon: **beta-galactosidase, lac permease, and transacetylase**.