Enzymes

Biology: AQA GCSE Higher, topic 2.2.1

Enzymes increase the speed of reactions. They are often called biological catalysts. An enzyme's active site is very important:

To catalyse (speed up) a reaction, the reacting chemical (substrate) must bind to the enzyme's active site.
The active site will only fit specific substrates.

The active site is like a lock and the substrate is like a key.
In the same way, there is usually only one enzyme for every substrate (or one key for each lock).

Test yourself on Enzymes

What happens if a substrate's shape does not match an enzyme's active site?
Name the three parts labelled in a diagram of an enzyme reaction where a substrate is broken down
Why is an enzyme's active site often compared to a lock, and its substrate to a key?
In the diagram, an enzyme breaks down its substrate into a product. What can be concluded about the product's structure?
Why is an enzyme's active site described as very important for its function?