Final answer:
Insulin is the 20th-century drug discovery that transformed type 1 diabetes from a fatal to a chronic disease, allowing management through regular injections.
Step-by-step explanation:
The 20th-century drug discovery that changed diabetes from a fatal disease to a chronic disease is insulin. Before the discovery of insulin, individuals with type 1 diabetes had little hope for survival, as their bodies could not produce insulin naturally. Insulin helps cells absorb glucose from the blood; therefore, without it, people with type 1 diabetes experience dangerously high blood glucose levels. With the advent of gene cloning technology, it became possible to produce human insulin using bacterial cells. This breakthrough has allowed for regular insulin injections to manage the condition effectively, transforming diabetes into a manageable chronic illness.
The 20th Century drug discovery that changed diabetes from a fatal disease to a chronic disease was insulin. Insulin helps cells take up glucose from the blood, and people with type 1 diabetes have a mutation in the gene that codes for insulin. In the past, the only treatment for type 1 diabetes was injecting insulin from outside sources. The discovery of insulin and the ability to produce human insulin in large quantities revolutionized the treatment of diabetes.