Protein that catalyses/speeds up reactions in cells
Enzymes
Can help break down molecules (digestion/respiration)
Can help build up molecules (Protein synthesis)
Rely on collisions of molecules with a specific region called the active site to work
How to make an enzyme
1. Instructions to make enzymes are written in the DNA
2. Genes are sections of DNA made of many bases, every 3 DNA bases codes for an amino acid
3. Amino acids are linked in chains and interact to fold into enzymes with specific active sites
4. Different genes code different order of amino acids which fold differently to form active sites specific to each substrate
Enzymes and temperature
Optimum temperature - the most successful collisions per unit time
Increasing collisions increasing reactions
Low kinetic energy, few collisions
Temperature above the optimum, denaturing begins
Enzymes and pH
Optimum pH
The further from the optimum, the rate of reaction decreases – some enzymes are inactive but they can recover
Denatured
High temperatures or extremes of pH change the shape of the active site of the enzyme. The substrate can no longer fit into the active site and so no reaction occurs.
Enzyme-substrate complex
If the substrate collides with the active site, it might fit in like a key into a lock.
Active site
Specific region of the enzyme where the substrate binds
Substrate
Molecule to be broken down
Product
Molecule formed from the substrate after the reaction
