L.O To learn how enzymes work and the conditions required for them to work.

Enzymes are the catalysts for all living processes

A catalyst is a substance that helps to speed up processes without being used up or changed in the reaction

Enzymes have a particular shape which allows them to bind to certain molecules. Each enzyme is unique and only fits the substrate that it is designed to fit.

Enzymes have an active site, which binds to the substrate; the substrate is the molecule being broken down by the enzymes.

This illustration highlights how an enzyme works



Rates of reactions

Rate of reaction

Rate of reaction 2



To make use of food, the food has to be broken down in our gut. Digestion is the process of breaking down large molecules in to smaller molecules , this process is usually aided by enzymes.


Digestive enzymes help to break down big molecules into smaller ones. The main digestive enzymes are amylase, protease and lipase.

  • Amylase helps to convert starch, which is a long chain of glucose into simple sugars. These simple sugars can then be easily absorbed. Amylase is found in three places within the body. It is found in the saliva, the pancreas and the small intestine
  • Protease helps to convert proteins, which are very large molecules into smaller molecules called amino acids. These protease enzymes are found in the pancreas, small intestine and the stomach
  • Lipase helps to convert lipids into two molecules called glycerol and fatty acids. Lipase is only found in two places the pancreas and the small intestine.


The body also has another way of dealing with the lipids that enter the body. Bile is produced by the liver and stored in the gall bladder. Bile is a substance which helps to break down fat into tiny droplets. This process is called emulsification. This gives the fat droplets a larger surface area and therefore easier for the lipase enzyme to break them down.



Uses of enzymes

Enzymes also have other uses. Enzymes are used in the washing up process. Enzymes can be used as biological detergents.  They are used to break down any lipids or fats present in the stains on the clothes and thus help to clean the clothes.

They can also be used to change foods. In baby foods protease enzymes are used to break down some proteins so it is pre digested and easier for the bay to digest

Enzymes can also be used in industry to help speed up certain reactions. There are many advantages to using them in industry but also many disadvantages.


  • The advantages are that the enzymes are very specific and help to lower cost and save energy.
  • However the disadvantages are that a small change in conditions can cause the enzymes to denature and enzymes are very expensive to produce.


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