Enzymes (CIE IGCSE Biology)
Revision Note
Author
LáraExpertise
Biology Lead
What Are Enzymes?
- Enzymes are:
- Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction
- Proteins
- Biological catalysts (biological because they are made in living cells, catalysts because they speed up the rate of chemical reactions without being changed)
- Necessary to all living organisms as they maintain reaction speeds of all metabolic reactions (all the reactions that keep an organism alive) at a rate that can sustain life
- For example, if we did not produce digestive enzymes, it would take around 2 - 3 weeks to digest one meal; with enzymes, it takes around 4 hours
How Do Enzymes Work?
Enzyme substrate specificity
- Enzymes are specific to one particular substrate (molecule/s that get broken down or joined together in the reaction) as the enzyme is a complementary shape to the substrate
- The product is made from the substrate(s) and is released
Enzyme specificity: lock and key model of enzyme activity
You've read 0 of your 0 free revision notes
Get unlimited access
to absolutely everything:
- Downloadable PDFs
- Unlimited Revision Notes
- Topic Questions
- Past Papers
- Model Answers
- Videos (Maths and Science)
Did this page help you?