Increasing Reaction Rates in Cells
Enzymes as catalysts
- Most chemical reactions either do not occur spontaneously or occur very slowly
- In laboratory or industrial settings, some chemical reactions require some sort of catalyst in order to form a sufficient concentration of product molecules
- Other conditions that may speed up the reaction rate include:
- High temperatures or pressures
- Extremes of pH
- High concentrations of the reactants
- Other conditions that may speed up the reaction rate include:
- Cells are very sensitive to extreme temperatures, pressures and pH-levels, so the chemical reactions occurring in them cannot be sped up by these means
- Enzymes are proteins that act as biological catalysts in cells and allow chemical reactions to occur at a suitable rate in the conditions found in living organisms
- They are reusable, so only a small number is needed to catalyse reactions
- They remain unchanged by the reactions that they catalyse
- Without the presence of enzymes, the rate of chemical reactions in organisms would be too low to support life
- To form product molecules, the reactants would need to collide at the correct angle and speed in order for a reaction to occur
- The chances of this occurring under normal conditions would be so low, that this would be an insignificant event
- Enzymes ensure that molecules (called substrate molecules) are orientated correctly and close enough for a reaction to occur
- The cell has control over the enzymes being produced, which in turn gives the cell control over the chemical reactions occurring in the cytoplasm