Hydrolysis can be understood by splitting the word up into ‘hydro’ which means water, and ‘lysis’ which means to break down. Essentially, a hydrolysis reaction is one that uses water to break down a substance.

When we digest our food, we break it down mechanically (e.g by using our teeth and churning our stomachs) and chemically (by producing enzymes.)

3 of the large molecules (macromolecules) found in food, that we need to break down for absorption include: 
1. Polysaccharides (carbohydrates)
2. Proteins
3. Lipids (fats)

These macromolecules are broken down through the process of hydrolysis.  This means that water is required to break the bonds in these macromolecules to make smaller molecules:
1. Monosaccharides 
2. Amino acids
3. Glycerol and fatty acids 

The hydrolysis reaction is extremely slow so your body produces enzymes to act as a catalyst. These enzymes are not directly involved in the reaction but just speed the process up: 

1. Amylase helps speed up the breakdown of polysaccharides to monosaccharides 
2. Pepsin and trypsin help speed up the breakdown of proteins to amino acids
3. Lipase helps speed up the breakdown of lipids to fatty acids and glycerol 

As mentioned before, water is essential in all these reactions. Therefore, hydrolysis in digestion causes bigger molecules to be broken down to smaller ones, with the help of digestive enzymes, to allow for absorption by the intestine. 


Biology

How does hydrolysis relate to digestion?

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