Before You Begin
Question #47701
The Question
Escherichia coli RY13 naturally produces the restriction endonuclease EcoRI as a defense against bacteriophages. If a targeted loss-of-function mutation is introduced into the endogenous gene encoding the site-specific DNA methyltransferase in this strain, which of the following will most likely occur?
Options
- A.
The bacterial genome will undergo autolytic cleavage by its own EcoRI enzymes, leading to cell death.
- B.
EcoRI will lose its ability to recognize the 5'-GAATTC-3' sequence due to the absence of methyl groups on the viral DNA.
- C.
The bacteria will become highly resistant to bacteriophage infection due to hyperactive restriction endonuclease activity.
- D.
The restriction endonuclease will be rapidly degraded by cellular proteases to prevent accidental host DNA damage.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Primary_vs_Secondary_Sewage_Treatment|Flocs_Formation|Activated_Sludge_Inoculum
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize restriction enzyme nomenclature and their cutting action but overlook the 'Modification' half of the R-M system.
The common misconception is that restriction enzymes inherently 'know' the difference between viral and host DNA, rather than relying on the biochemical tag of methylation for host protection.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Flocs Formation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |