Enzymes Flashcards
What biological molecule are enzymes made out of?
Proteins
What are enzymes?
Biological catalysts
What do anabolic enzymes do?
Builds molecules
What do catabolic enzymes do?
Breaks down molecules
Enzymes provide an area in which a reaction can happen by…?
Actively forcing a reaction
Can enzymes be used repeatedly?
Yes
Define active site
An area on which an enzyme-substrate binds
Define tertiary structure
A 3D shape which is caused by bonds and interactions
Define intracellular enzymes
Enzymes which catalyse reactions inside a cell
Define extracellular enzymes
Enzymes which catalyse reactions outside a cell
An enzyme has a … centre and a … outside
An enzyme has a hydrophobic centre and a hydrophilic outside
Why does the pH affect enzymes?
As the extra H+ ions disrupt the hydrogen and ionic bonding within a molecule
How does pH denature enzymes?
When the hydrogen and ionic bonds are disrupted, this can lead to the active site altering in structure or change. Some active sites have specific charges that allow it to bond with specific substrates. Therefore, the pH hinders bonding ability.
How does temperature denature enzymes?
A high-temperature causes vibrations within the molecule. This weakens the bonds within the tertiary structure. This changes the 3D shape, which causes a change in structure and a proteins (enzymes’) job is reliant on its structure
Name the two enzyme theories
Lock and Key
Induced Fit Theory
What is the Lock and Key theory?
Once the substrate with the correct shape enters the active site, a reaction will occur. This is because the active site is directly complementary to the substrate shape.
What is the Induced Fit theory?
The substrate collides with the active site and the active site changes shape due to attractive charges. The change in shape destabilises the substrate and helps to weaken and break bonds
What is an enzyme-substrate complex?
Combination of the substrate and enzyme
What is a competitive inhibitor?
A substance that slows down an enzyme reaction in any way
How does a competitive inhibitor slow down an enzyme reaction?
It blocks the active site by binding briefly with it
Why can’t enzymes catalyse competitive inhibitors?
Because enzymes are specific
The change in shape that most competitive inhibitors cause is…?
Reversible
What is a non-competitive inhibitor?
A substance that binds permanently to the enzymes allosteric site
What does a non-competitive inhibitor cause?
Irreversible damage so the enzyme denatures
What is a cofactor?
A substance that helps to control the rate of enzyme reactions. Some are attached to the molecule
What is a coenzyme?
Organic molecules that bind briefly to the active site before or at the same time as the substrate
Why may coenzymes not be able to be reused?
When the enzymes reaction is finished, the coenzyme may be changed
