Question

The mismatch repair system of E. coli is:

• A. Prenyl directed repair system
• B. Cysteine directed system
• C. Mutated system
• D. Methyl directed system

Hint:

The methyl-directed mismatch repair system in E. coli uses methylation to identify the correct DNA strand.

Answer 1

The Correct Option is D

Step 1: Understanding the Mismatch Repair System 
In E. coli, the mismatch repair system corrects errors that occur during DNA replication, specifically by recognizing the parent strand through methylation. 
Step 2: Evaluating the Options 
- Prenyl directed repair system: Not related to the mismatch repair system. 
- Cysteine directed system: Incorrect, does not relate to mismatch repair. 
- Mutated system: Incorrect, as the system is not considered mutated. 
- Methyl directed system: Correct, the system uses methylation marks on the parent strand to identify and correct mismatches. 
Step 3: Conclusion 
The mismatch repair system in E. coli is methyl-directed, recognizing the parent strand by methylation.