Enzymes

Topic 3.6

3.6.1 & 3.6.4: Key Terms about enzymes

Enzyme structure

3.6.2: Specificity

Metabolic pathways consist of chains and cycles of enzyme-catalyzed reactions. Enzymes have the ability to bind substrates because of the presence of an active site (i.e., part of an enzyme molecule where a substrate attaches by weak chemical bonds. The active site is usually a pocket or groove on the surface of the enzyme. A substrate is a substance on which an enzyme acts. Enzymes will only bind with a specific substrate or substrates. Figure 4 outlines the lock-and-key model and the induce fit model which explain enzyme-substrate specificity.

Figure 1: Model of enzyme-substrate specificity

Enzyme specificity

3.6.3: Factors affecting enzyme activity

Figure 2: Effect of temperature on enzyme actitiy

Enzyme specificity

Explain temperature's effect on enzyme activity?

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Temperature and enzyme actitivy

Figure 3: Effect of pH on enzyme activity

Activation energy

Examine Figure 3 to describe how pH affects enzyme activity?

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Activation energy explained

Figure 4: Effect of substrate concentration on enzyme activity

Enzyme specificity

Explain the effect of substrate concentration on enzyme activity?

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Activation energy explained

3.6.5: The use of lactase in the production of lactose-free milk

Figure 5: Making lactose-free milk

Enzyme specificity

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