Learn: Enzymes as Biological Catalysts

Welcome!Great to see you again! You've already learned about cells, diffusion, osmosis, and active transport. Today, we'll build on that foundation by exploring enzymes, which play a vital role in how cells function.

What Are Enzymes?Enzymes are biological catalysts. They speed up chemical reactions in living organisms without being used up themselves. This helps cells work efficiently and saves energy.

Why Are Enzymes Important?Enzymes are essential for processes like digestion, respiration, and photosynthesis. Without them, reactions in your body would happen too slowly to keep you alive. For example, enzymes break down food into smaller molecules your cells can use.

How Do Enzymes Work?Enzymes work by binding to specific molecules called substrates. This happens at the enzyme's active site, which is shaped to fit the substrate exactly. When the substrate and enzyme bind, it forms an enzyme–substrate complex, allowing the reaction to occur.

The Lock-and-Key ModelThe lock-and-key model explains how enzymes work. The substrate fits into the active site like a key fits into a lock. This ensures that enzymes are highly specific to the reactions they catalyse.

Factors Affecting Enzyme ActivityEnzyme activity can be affected by temperature, pH, and the concentration of substrates. For example, high temperatures can denature (damage) enzymes, while extreme pH levels can change their shape.

DenaturationDenaturation happens when an enzyme loses its shape due to high temperature or extreme pH. This prevents the substrate from binding to the active site, stopping the enzyme's function.

Review Time!You've learned about enzymes, how they work, and the factors that affect their activity. Let's test your understanding with a few questions.