OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Why is the discovery of DNA considered significant in biology?

1. It determined how proteins are formed

2. It led to the identification of all human genes

3. It established DNA as the code for life

4. It provided a method for cloning organisms

The correct answer is: It established DNA as the code for life

The discovery of DNA is considered significant in biology primarily because it established DNA as the code for life. This finding revealed that DNA carries the genetic instructions essential for the growth, development, functioning, and reproduction of all living organisms. Understanding that DNA serves as the molecular blueprint for life forms has had profound implications in various fields, including genetics, medicine, and evolutionary biology. The structure of DNA, identified as a double helix by Watson and Crick, elucidates how genetic information is stored and transmitted across generations through the sequences of nucleotide bases. This foundational knowledge has led to advances in genetic engineering, biotechnology, and the understanding of heredity and variation within species. As a result, the role of DNA as the genetic material is a cornerstone of modern biological science, fundamentally shaping our comprehension of life's processes. While the identification of all human genes, the methods for cloning, and the understanding of protein formation are all important milestones in biology that were influenced by the discovery of DNA, they are secondary to the central role that DNA plays as the fundamental code that defines biological inheritance and functionality.