Final answer:
The pole vaulting analogy helps explain how enzymes lower the activation energy barrier of chemical reactions, similar to reducing the height of the bar, making it easier for reactants to become products.
Step-by-step explanation:
The analogy of pole vaulting, where vaulters must clear a bar at increasing heights, is a good way to understand enzymes and activation energy. As the bar is placed higher, it becomes more difficult to clear it, similar to how higher activation energy makes a chemical reaction more difficult to proceed. Enzymes work like a tool that lowers the height of the bar, or in chemical terms, they lower the activation energy required for a reaction. This allows reactants to overcome the barrier more easily and become products, as depicted in potential energy diagrams where a lower energy 'hill' has to be surmounted.
Endothermic (energy-absorbing) and exothermic (energy-releasing) reactions both have an activation energy (Ea) barrier that reactants must overcome. Enzymes function by decreasing this barrier, thereby accelerating the reaction rate. Without enzymes, the activation barrier would be too high for many biochemical reactions to occur at a significant pace under normal conditions of temperature and pressure.