Why is pro insulin so called ? How is insulin different form it?

Explain structure of Insulin. How insulin is synthesised in human (or mammals)? Why is proinsulin so called? How is insulin different from it?

Why is porinsulin so called ? How is insulin differnet form it?

How does insulin deficiency occur ?

How did Eli Lilly Company go about preparing the human insulin? How is the insulin thus produced different from that produced by the functional human insulin gene?

What is insulin? Where is it formed?

How is the insulin produced by human body different from the insulin produced by the above-mentioned company ?

How is a mature, functional insulin hormone different from its pro-hormone?