A Level Biology Practice Exam

What is the induced-fit hypothesis related to?

1. Enzyme function and substrate interaction

2. The theory of DNA replication

3. Protein folding and functionality

4. The mechanism of cellular respiration

The correct answer is: Enzyme function and substrate interaction

The induced-fit hypothesis is specifically related to enzyme function and how enzymes interact with their substrates. This concept suggests that when a substrate approaches an enzyme, the enzyme's active site undergoes a conformational change that allows a better fit between the enzyme and the substrate. This dynamic interaction enhances the enzyme's ability to catalyze the reaction by stabilizing the transition state, making it easier for the reaction to occur. This hypothesis contrasts with the older lock-and-key model, which suggested that enzymes and substrates perfectly fit together without any changes. In reality, the flexibility and adaptability of enzyme structures play a crucial role in their activity, which is precisely what the induced-fit hypothesis highlights. Understanding this mechanism is vital for grasping how enzymes function in biological processes, including metabolic pathways, signaling, and regulation.