Question

Given below are the sequence of events in the production of human insulin by Eli Lilly.
a) Preparation of two DNA sequences corresponding to chain A and B of human insulin.
b) Production of chain A and B separately.
c) Introduction of chains in plasmids of E.coli.
d) Extraction of chain A and B combining them by creating disulphide bonds.
Choose the correct sequence of events.

• A. (a), (b), (c), (d)
• B. (a), (c), (b), (d)
• C. (a), (b), (d), (c)
• D. (a), (d), (b), (c)

Hint:

You must put the genes into the bacteria (c) before the bacteria can produce the protein chains (b). This naturally orders a $\rightarrow$ c $\rightarrow$ b $\rightarrow$ d.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept: The commercial production of synthetic human insulin (Humulin) involves specific recombinant DNA techniques pioneered by the American company Eli Lilly in 1983.
Step 2: Key Formula or Approach: Arrange the distinct steps of recombinant protein production in logical chronological order.
Step 3: Detailed Explanation: The logical sequence of biotechnological events is as follows:
First, the scientists had to prepare the specific genetic codes, meaning the preparation of two DNA sequences corresponding to chain A and chain B of human insulin (Step a).
Second, these synthesized DNA sequences were introduced into the plasmids of E. coli bacteria to serve as vectors (Step c).
Third, the engineered E. coli were cultured, leading to the biological production of chain A and chain B separately within the bacterial cells (Step b).
Finally, these synthesized chains were extracted from the bacteria, purified, and then chemically combined by creating disulfide bonds to form mature, functional human insulin (Step d).
The correct chronological sequence is a $\rightarrow$ c $\rightarrow$ b $\rightarrow$ d.
Step 4: Final Answer: The correct option is (2).