B4 - Enzymes Flashcards
What are enzymes?
Proteins that function as biological catalysts.
What is a catalyst?
A substance which increases the rate of reaction, without being changed or used up in the reaction.
What is a substrate?
A molecule that is changed in a reaction.
How do enzymes and substrates work together?
An enzyme has a shape that is complementary to (matches) the shape of the substrate molecules that bond to it. When the substrate molecule binds to an enzume, it is changed to a product and then released.
What is the active site?
The part of an enzyme where the substrate binds. It must be complementary to the substrate for the substrate to fit.
What forms when a substrate binds to an enzyme?
A temporary enzyme-substrate complex.
Why are enzymes necessary?
They maintain reaction speeds of all metabolic reactions at a rate that can sustain life.
What is the molecule formed by the substrate called?
The product.
What are the seven properties of enzymes?
- Made of protein
- Act as biological catalysts
- Specific to a particular substrate
- Re-usable
- Sensitive to temperature
- Sensitive to pH
- Catalyse one particular reaction
What is the temperature called where the enzyme is the most active?
Optimum temperature.
What happens to the rate of reaction before the optimum temperature?
Increases till it gets to the optimum temperature.
What happens to the rate of reaction after the optimum temperature?
Decreases till the temperature gets too high and the enzyme denatures.
Why does an enyme denature?
Some of the bonds holding the enzyme together break, changing the active site.
Why does a higher temperature increase the rate of reaction?
Substrates have more kinetic energy and move faster and therefore collide with more enzymes.
What is a successful collision?
When the enzyme and substrate bump into each other with sufficient energy for a chemical reaction to take place.
