Final answer:
The one-gene/one-enzyme hypothesis was an early concept suggesting a gene encodes a single enzyme, which was revised to the one-gene-one polypeptide hypothesis due to the discovery of functional RNAs and proteins composed of multiple polypeptides.
Step-by-step explanation:
The one-gene/one-enzyme hypothesis was initially proposed by George Beadle and Edward Tatum to explain the relationship between genes and the production of enzymes, whereby one gene was responsible for the production of one enzyme. However, this was later revised to the "one gene-one polypeptide" hypothesis. The original hypothesis was found to be limited because not all genes encode enzymes; some genes encode functional RNA molecules, like tRNAs or rRNAs, which do not function as enzymes but are vital for protein synthesis. Additionally, many proteins are composed of multiple polypeptides, which means they are encoded by more than one gene. The discovery of ribozymes also challenged the hypothesis, as these RNA molecules have been found to act as catalysts in various biological reactions, similar to enzymes.
The one-gene/one-enzyme hypothesis was important because it provided a framework that led to a deeper understanding of gene function, but scientific advancements showed that it was an oversimplification of the complex and varied nature of how genetic information produces cellular components and functionalities.