Proteins Catalysts and Enzymes

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Protein molecules are very important in your body. A protein molecule is made up of long chains of amino acids. These long chains are folded to produce a specific shape that enables other molecules (substrates) to fit into the protein. We call this the active site

Proteins act as:-

  • structural components such as muscles and tendons 
  • hormones such as insulin 
  • anitbodies, which destroy pathogens 
  • catalysts in the form of enzymes

Catalysts increase the rate of chemical reactions. Biological catalysts are called enzymes. Enzymes are proteins.


Chemical reactions are controlled by enzymes. The shape of an enzyme is vital for the enzyme's function, high temperatures change the shape. Enzymes do not change a reaction in any way- they just make it faster. Different enzymes work best at different PH values 

How do enzymes work?

The substrate (rectant) of the reaction fits into the active site of the enzyme, once it is in place the substrate and the enzyme fit together. The reaction then takes place rapidly and the products are released from the surface of the enzyme.  


Some enzymes work outside the body cells.

The digestive enzymes are produced by specialised cells in glands and in the lining of…


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