Enzymes are biological catalysts produced by living cells. Like all catalysts, they greatly speed up all the processes that go on inside living organisms. A single cell may contain 100,000 different enzymes, which are needed to take part in its 1,000 to 2,000 chemical reactions. For example digestive enzymes break down food into simpler substances. Many enzymes work in the opposite way, linking simple substances together to form larger, more complex ones needed to build up tissues. Enzymes themselves are made of protein and each one has a differently shaped active site, where the reaction takes place.

It is this shape which dedicates it to a particular chemical reaction.

This can be described as a lock and key system, whereby the two substances to be linked, the keys, fit into the enzyme, the lock. Only the correctly shaped substances can fit into the lock.

2) To the first, using a pipette, add hydrochloric acid, vinegar to the second, nothing to the third, sodium bicarbonate to the fourth and to the fifth add caustic soda, until the test tubes are of pH 1, 4, 7, 10, 14(test with litmus paper).

The testing will be done at room temperature in test tubes of the same size at an amylase to starch ratio of 1:5

1.One substance and 2.Substance fits into enzyme 3.Two separate an enzyme and is broken down substances are released

In an experiment such as this there are many variables which will effect the results.

Some common words found in the essay are:
Enzymes Enzymes, Fair Testing, Pipette Measuring, Activity Aim, active site, enzyme activity, test tubes, Equipment Test, ph enzyme, starch solution, change temperature, mean result, reaction takes, stop clock, variables constant,
Approximate Word count = 741
Approximate Pages = 3 (250 words per page double spaced)