Select the two correct statements out of the four (1-4) given below about lac operon.
1. Glucose or galactose may bind with the repressor and inactivate it
2. In the absence of lactose the repressor binds with the operator region
3. The z-gene codes for permease
4. This was elucidated Francois Jacob and Jacque Monod
The correct statements are :

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iii)
D. (ii) and (iv)

Explanation

To solve the question regarding the lac operon, we need to evaluate each of the four statements provided and determine which two are correct.

### Step-by-Step Solution:

1. **Understanding the Lac Operon**:
The lac operon is a segment of DNA that contains genes responsible for the metabolism of lactose in bacteria. It consists of structural genes (lacZ, lacY, and lacA) and regulatory elements (promoter and operator).

2. **Analyzing Statement 1**:
- **Statement**: "Glucose or galactose may bind with the repressor and inactivate it."
- **Evaluation**: This statement is incorrect. The repressor is inactivated by lactose, not glucose or galactose.

3. **Analyzing Statement 2**:
- **Statement**: "In the absence of lactose, the repressor binds with the operator region."
- **Evaluation**: This statement is correct. When lactose is not present, the repressor binds to the operator, preventing transcription of the downstream genes.

4. **Analyzing Statement 3**:
- **Statement**: "The z-gene codes for permease."
- **Evaluation**: This statement is incorrect. The lacZ gene actually codes for beta-galactosidase, while the lacY gene codes for permease.

5. **Analyzing Statement 4**:
- **Statement**: "This was elucidated by Francois Jacob and Jacque Monod."
- **Evaluation**: This statement is correct. The lac operon model was indeed elucidated by François Jacob and Jacques Monod, who conducted significant research on gene regulation.

6. **Conclusion**:
The two correct statements about the lac operon are:
- Statement 2: "In the absence of lactose, the repressor binds with the operator region."
- Statement 4: "This was elucidated by Francois Jacob and Jacque Monod."

### Final Answer:
The correct statements are: **2 and 4.**

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