Enzymes (Edexcel GCSE Chemistry)

Enzymes

• Enzymes are nature’s catalysts

• They are biological substances that catalyse reactions in living cells

• Enzymes are biological catalysts made from protein

• Enzymes speed up chemical reactions in cells, allowing reactions to occur at much faster speeds than they would without enzymes at relatively low temperatures (such as human body temperature)

• Important reactions that are biologically catalysed include respiration, photosynthesis and protein synthesis

• The production of alcohol by the fermentation of sugars occurs in the presence of a biological catalyst, yeast enzymes:

C₆H₁₂O₆ + enzymes → 2CO₂ + 2C₂H₅OH

• This reaction is very important to the production of alcoholic drinks such as beer and wine

• Not only do enzymes work at low temperatures, but they are very selective and will only work on very specific molecules when presented with a mixture of reactants

Enzymes are very selective which means they will work only on molecules which have exactly the right shape to fit into the active site of the enzyme