B2- Enzymes Flashcards
What are enzymes?
Enzymes are catalysts produced by living things.
What is a catalyst?
A catalyst is a substance that increases the speed of a reaction without being changed or used up in the reaction.
What are enzymes made of?
Enzymes are large proteins made up of chains of amino acids.
Why do enzymes have unique shapes?
Enzymes have unique shapes so they can catalyse specific reactions.
What is the substrate in enzyme reactions?
The substance that an enzyme acts on is called the substrate.
What is the ‘lock and key’ model?
The ‘lock and key’ model illustrates how an enzyme’s active site fits the substrate.
What is the ‘induced fit’ model?
The ‘induced fit’ model describes how the active site changes shape slightly to fit the substrate better.
What happens to enzymes at high temperatures?
At high temperatures, bonds in the enzyme may break, changing its shape and causing it to be denatured.
What is denaturation in enzymes?
Denaturation is when the enzyme’s active site changes shape, preventing the substrate from fitting.
What is the optimum temperature for enzymes?
All enzymes have an optimum temperature where they are most active.
How does pH affect enzyme activity?
pH affects the bonds holding the enzyme together; if too high or low, it can denature the enzyme.
What is the optimum pH for most enzymes?
The optimum pH for most enzymes is often neutral pH 7.
What is the optimum pH for pepsin?
Pepsin works best at pH 2.
Fill in the blank: Enzymes are ______ produced by living things.
[catalysts]
True or False: All enzymes catalyse multiple different reactions.
False
