- Enzymes are proteins which functions as a catalyst to speed up biological chemical reactions
- Catalysts are substances that speed up a reaction without being changed or used in the reaction
- Biological enzymes keep reaction speeds at ones that can sustain life
- The substance which an enzyme acts on is called the substrate
- Each enzyme specifically works for only one substrate as the active site (the area which reacts with the substance) has a specific shape so that only that one substrate can fit in the active site almost like puzzle pieces, and react
- The lock and key model is the theory of how the enzyme's active site complements the shape of the substrate
- After the substrate and enzyme have joined together through the lock and key model, chemical reactions happen and the products of the substrate leave as their shapes change so that they no longer fit the enzyme
- The enzyme does not change after the reaction
However, enzyme activity can be affected by some factors. Two that you need to learn are temperature and pH level.
Temperature
- At a higher temperature, particles gain more kinetic energy from the heat, and therefore collide more
- This means that the enzymes and substrates will be collide more and react
- Therefore, when the temperature rises, the enzyme activity will have a higher rate of reaction
- However, at a certain point of high temperature, the shape of the enzyme will start to change, which is called denaturing and can no longer function
- Once the enzyme has reached this point, the rate of enzyme activity will become slower
pH
- The pH of a solution can change the shape of the active site
- Enzymes work at an optimal pH level
- This means that the rate of reaction is greater as it approaches or gets close to optimal pH level
- An extreme pH level may change the shape and denature the enzyme, sharply decreasing the enzyme activity
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