Enzymes Flashcards
Define enzymes.
They are biological catalysts which speed up chemical reactions.
How do enzymes work?
The substrate collides with the active site and becomes attached.
Enzyme catalyses breakdown of substrate.
Products are released from the active site.
Explain the lock and key hypothesis.
The substrate (key) must be the exact shape to fit in the enzyme’s active site (lock).
How does temperature affect enzyme activity?
At low temps, the molecules gain kinetic energy and collide more frequently.
At high temps, the enzyme is denatured which causes less reactions.
How does pH affect enzyme activity?
Each enzyme has their own optimum pH.
At low temps, an increase in temp increases the rate of an enzyme-catalysed reaction.
How does enzyme concentration affect enzyme activity?
As the amount of enzymes inc, the rate of reaction inc because more enzymes can speed up the break down of substrates.
How does the substrate concentration affect enzyme activity?
An inc in the substrate concentration means that the more of the enzyme molecules can be used.
What is used to test for protein and what colour is it when protein is present?
Biuret.
Turns purple.
What is used to test for sugars and what colour is it when sugars is present?
Benedicts.
Turns green, yellow, orange or red.
What is used to test for starch and what colour is it when starch is present?
Iodine.
Turns blue / black.
What is used to test for lipids and what colour is it when lipids is present?
Ethanol.
Turns cloudy white
