Enzymes & Temperature | Biology for GCSE/IGCSE - Year 11 PDF Download

Enzymes & Temperature: Extended

• Enzymes, being proteins, possess a specific shape upheld by bonds.
• This structural specificity is particularly critical around the active site, ensuring that the substrate fits precisely, enabling the reaction to proceed.
• Enzymes exhibit optimal activity at their designated temperature, such as the human body's standard of 37⁰C.
• Excessive heating, surpassing the optimal temperature, disrupts these bonds, causing the enzyme to lose its shape—a phenomenon termed denaturation.
• Denatured enzymes lose their active site conformation, rendering them incapable of accommodating substrates.
• Denaturation is a permanent alteration; once enzymes undergo this process, they cannot recover their original shape, leading to a cessation of enzymatic activity.

Effect of Temperature on Enzyme Activity

• Increasing the temperature from 0°C to the optimum increases the activity of enzymes. This is because higher temperatures provide more energy to the molecules, causing them to move faster and increasing the number of collisions with substrate molecules. As a result, the rate of reaction speeds up.
• This means that low temperatures do not denature enzymes; they simply slow down the enzymatic activity.