Learn: Enzymes in Living Systems (Factors Affecting Rate)

Welcome!Building on what you've already learned about cell membranes and transport mechanisms, this lesson will help you understand how enzymes function and what factors affect their activity. Let's dive in!

What are Enzymes?Enzymes are biological catalysts. They speed up chemical reactions in cells without being used up themselves. This is vital for processes like digestion, respiration, and DNA replication.

How Do Enzymes Work?Enzymes bind to specific molecules called substrates at their active site. This forms an enzyme-substrate complex, leading to a reaction that forms products. The shape of the active site is highly specific to the substrate.

Factors Affecting Enzyme ActivityThe activity of enzymes is influenced by several factors, including temperature, pH, substrate concentration, and enzyme concentration. Let's explore these in detail.

Temperature and Enzyme ActivityTemperature affects the speed of enzyme reactions. Higher temperatures increase the kinetic energy of molecules, leading to more frequent collisions between enzymes and substrates. However, if the temperature is too high, enzymes can become denatured and lose their function.

pH and Enzyme ActivityEnzymes work best at an optimum pH. Extreme pH levels can disrupt the bonds holding the enzyme's structure, leading to denaturation. For example, digestive enzymes like pepsin function in acidic environments, while others like amylase work in alkaline conditions.

Substrate ConcentrationAs substrate concentration increases, enzyme activity also increases—up to a point. When all enzyme active sites are occupied, the reaction rate plateaus. This is called saturation.

Enzyme ConcentrationIncreasing enzyme concentration generally increases the reaction rate, provided there is enough substrate. If substrate levels are limited, adding more enzymes will not affect the rate.

Review Time!Great work! You've learned how enzymes work and the factors affecting their activity. Let's test your understanding with a few questions.