1. (Oxidation of oxygen) Respiration C6 H12 O6 + O2 ---> Energy + CO2 + H2O
Substrate Released Product
2. Combustion (adding energy) = Without an enzyme - to break down glucose ---> carbon dioxide and water - we have to put energy into the glucose molecule bonds before they break and release a lot of energy.
3. Energy of Activation = initial energy added to glucose molecules.
The shape of the active site is affected by pH. This is why enzymes will only work at a specific pH, as well as a specific temperature. Change the pH (acidic) and the enzyme stops working.
Increasing the temperature to 60°C will cause a permanent change to the shape of the active site. This is why enzymes stop working when they are heated. We say they have become denatured.
Biological systems overcome the energy of activation by THE ENZYME.