Enzymes Flashcards
What type of protein are enzymes?
globular
What is the active site on an enzyme?
A depression on the surface. It is where the substrate binds.
What is an enzyme-substrate complex?
when the substate collides with and binds to the enzyme an enzyme-substrate complex is created.
What is the lock and key model?
The substrate is likened to a key, which fits the enzymes lock.
How many substrates will each enzyme catalyse?
Each enzyme will only catalyse one specific reaction ad only one shape of substrate will fit precisely into the active site.
What is the induced fit theory of enzyme action?
Evidence has shown that the active site of an enzyme is flexible. When the substrate enters the active site, the enzyme changes shape slightly, fitting metre closely around the substrate.
What does it mean when enzymes are called biological catalysts?
They speed up reactions that would otherwise happen very slowly.
What do enzymes do?
Some join small molecules together to make larger molecules.
Others breakdown larger molecules into smaller molecules.
Why do enzymes have different shaped active sites?
Due to different primary and tertiary structures.
When do enzymes denature? Why?
At high temperatures and at extreme pH because the intermolecular bonds are broken.
What happens to the peptide bonds when enzymes denature?
Are not broken but the chain unravels and loses its precise 3D shape.
How do enzymes speed up a metabolic reaction?
- To convert substrates to products bonds must be broken
- Activation energy is needed to start a reaction.
- Activation energy is provided by heating a substance.
- Enzymes reduce the activation energy.
What happens when the enzyme-substrate complex is formed?
- The substrate forms temporary bonds with the R groups in the active site.
What happens if two substrate molecules need to be joined?
The enzyme can hold them together and overcome any repulsion.
What happens if a substrate needs to be broken down?
Fitting into the active site can distort the substrate and but strain on the bonds and break them.
