chemistry coursework

Enzymes Research
Enzyme optimum temperature The graph on the left compares enzymes activity with the temperature the enzymes are in. The optimum temperature for enzymes is 40 degrees but anywhere above that temperature the enzymes activity rapidly decreases because the enzymes denatures.

Enzyme optimum pH

This graph compares the enzyme activity with the pH it is at for intestinal enzymes. The optimum pH for enzymes changes depending on where the enzyme is for example intestinal enzymes have a pH optimum of around 7.5 whereas stomach enzymes have a pH optimum of about 2. The enzymes also denature if they exceed there optimum temperature by a certain amount depending on the enzyme
How enzymes work
Enzymes are biological catalysts. They are proteins folded into complex shapes that allow smaller molecules (substrate molecules) to fit inside them. The place where these substrate molecules fit into is called the active site. The enzymes are denatured if the shape of the enzyme changes and the active site will no longer work.
The enzymes involved in respiration, photosynthesis and protein synthesis work inside cells. Other enzymes are produced by specialised cells and released from them. The digestive enzymes are like this. They pass out into the gut, where they catalyse the breakdown of food molecules.

Different enzymes catalyse different reactions. The table below shows three enzymes and which reaction they catalyse.
Enzyme
Reaction catalysed
Amylase
Starch → sugars
Protease
Proteins → amino acids
Lipase
Lipids → fatty acids + glycerol

Different parts of the gut produce different enzymes. The table below shows where three different enzymes are produced.
Enzyme
Where produced
Amylase
Salivary glands, pancreas, small intestine
Protease
Stomach, pancreas, small intestine
Lipase
Pancreas, small intestine

Each enzyme has a different use. Below is a list of four enzymes and their use.
Enzyme
Use
Protease
Used to pre-digest proteins during the manufacture of baby foods
Lipase
Used - together with protease - in biological detergents to break down (digest) the substances in stains into smaller, water soluble substances
Carbohydrase
Used to convert starch syrup, which is relatively cheap, into sugar syrup, which is more valuable - for example, as an ingredient in sports drinks
Isomerase
Used to convert glucose syrup into fructose syrup - fructose is sweeter than glucose, so it can be used in smaller amounts in slimming foods