In humans, insulin is manufactured in the pacreas in humans, insulin is manufactured in the pancreas. insulin is a peptide hormone that causes the body cells to take up glucose. the blueprint for the polypeptide chain is insulin is found in the of specialized pancreatic cells

DNA

Explanation:

It is in the DNA molecule that is the code for the production of a polypeptide chain, with insulin no different. Thus, we can say that the blueprint for a polypeptide chain is the insulin found in specialized pancreatic cell DNA.

In summary, the synthesis of a polypeptide chain can be outlined as:

DNA -> RNA -> Protein

However, this simple scheme is more complex than it looks. Thus, to facilitate research, the scientists decided to split and study the steps for protein synthesis separately. Thus, the two steps of protein synthesis originated:

DNA stage -> RNA (transcription)

RNA Step -> Protein