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Question #45134
The Question
A biotechnology firm attempts to produce human insulin by inserting the complete human proinsulin cDNA into an E. coli expression vector. Although the recombinant bacteria successfully translate the inserted sequence, the purified protein fails to exhibit biological activity in diabetic models. Which of the following is the primary reason for this failure?
Options
- A.
E. coli lacks the post-translational machinery required to excise the C-peptide, resulting in an inactive prohormone.
- B.
The absence of spliceosomes in E. coli prevents the excision of the C-peptide sequence from the mRNA transcript.
- C.
Bacterial ribosomes cannot synthesize the disulfide bridges required to link the A and B chains.
- D.
The C-peptide induces the formation of insoluble inclusion bodies by breaking the peptide bonds between the A and B chains.
Check Your Answer
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
Proinsulin|C-peptide_cleavage|Disulfide_bridge_formation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between transcriptional processing (intron splicing) and post-translational modification (polypeptide cleavage).
Students frequently confuse the 'removal of C-peptide' with the 'removal of introns', or fail to recognize the exact reason why Eli Lilly had to synthesize the A and B chains separately in E. coli (because prokaryotes cannot process the prohormone).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology and Its Applications - Class 12 |
| Concept | Insulin Chain Maturation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |