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Question #47683
The Question
A patient exhibits severe diabetes mellitus despite normal transcription and translation of the insulin gene. Blood analysis reveals high levels of a single, continuous polypeptide containing A, B, and C chains, but no bioactive insulin. Which of the following statements correctly explains this physiological failure and accurately contrasts it with the commercial production of recombinant human insulin?
Options
- A.
The patient lacks the enzymes to excise the C-peptide; whereas in commercial production, E. coli utilizes its endogenous proteases to cleave the C-peptide from pro-insulin.
- B.
The patient has a defect in post-translational modification preventing C-peptide removal; whereas in commercial production, DNA sequences for chains A and B are introduced separately into E. coli to bypass this processing step.
- C.
The patient fails to form disulfide bonds between the A and C chains in the Golgi apparatus; whereas in commercial production, chains A and B are linked by disulfide bonds in vivo within the bioreactor.
- D.
The patient's pro-insulin lacks the B chain due to a splicing error; whereas in commercial production, the C-peptide is synthesized separately to act as a chaperone for A and B chain assembly.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Trichoderma_polysporum|T-lymphocytes|Cyclosporin A|Autoimmunity Principles
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Understanding the limitation of prokaryotic expression systems.
Students often memorize that Eli Lilly produced insulin but fail to connect WHY they had to synthesize chains A and B separately—because bacteria lack the eukaryotic post-translational machinery (enzymes) to excise the C-peptide from pro-insulin.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Bioactive Molecule Origin |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |