Enzyme action Flashcards
What are enzymes?
Enzymes are globular proteins that act as catalysts.
What are catalysts?
Catalysts alter the rate of a chemical reaction without changing their shape and they can be used over and over again.
What conditions are needed for a reaction to take place naturally?
- Reactants must collide with sufficient energy.
- The end product must have less energy than the reactants.
- Activation energy is required to start the reaction.
How do enzymes increase the rate of reaction?
In every reaction, there is an activation energy level which needed to be overcome to start the reaction. Enzymes work to lower this activation energy and allows the reaction to start with lower energy, therefore, it increases the RoR.
What is an active site?
A specific region on the enzyme surface where substrates bind, and where the chemical reaction catalyzed by the enzyme occurs.
Active sites are is made up of a relatively small number of amino acids.
What is the name of the molecule which the enzyme acts upon?
A substrate.
What is the name of the compound when the enzyme and substrate react together?
An enzyme-substrate complex. The substrate molecule is held within the active site by temporary weak bonds e.g. hydrogen bonds, formed between certain amino acids of the active site and groups of the substrate molecule.
What is the induced fit model of enzyme action?
- The active site and the substrate are not complementary to each other before they collide.
- When the substrate binds to the active site, it causes the active site to change shape and become complementary to the substrate.
- As the enzyme changes shape, it puts a strain on the substrate which distorts a particular bond in the substrate which reduces the activation energy needed to complete the reaction.
What’s the difference between the induced fit and lock-key model?
In the lock-key model, the active site of the enzyme and the substrate are complementary to each other BEFORE they collide.
Explain why the induced fit model is a better explanation of enzyme action than the lock-key model.
Because induced fit can explain how activation energy is reduced and scientists observed that other molecules bind to other sites other than the active site, therefore, it supports the idea that enzyme’s structure is flexible and induced fit model supports the idea that it’s flexible.
