Biology·Organisation & maintenance · NSSCO 3.5
Enzymes — biological catalysts
Narrated lesson · press play
The protein machines that speed up life's reactions — the active site and lock-and-key fit, and how temperature and pH change enzyme activity, including denaturation.
What you'll learn in this lesson
By the end you should be able to (NSSCO Biology 3.5):
- Define a catalyst as a substance that speeds up a reaction and is not used up by it
- Define enzymes as proteins that act as biological catalysts
- Explain enzyme action using active site, substrate, enzyme-substrate complex and product
- Explain the effect of temperature and pH on enzyme activity in terms of shape, fit and denaturation
- Describe everyday uses of enzymes (e.g. biological washing powders, the food industry)
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Quick revision
Revise this in 5 minutes
Miss Rachel and Mike talk through the whole topic — with the figure and working drawn live.
Hands-on lab
Investigate how temperature affects an enzyme in 3D