B4

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  • Created by: 11mbrady
  • Created on: 09-02-16 18:49

B4

ENZYMES

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Enzymes

ENZYMES are proteins that SPEED UP CHEMICAL REACTIONS

The instructions for making enzymes and other proteins are found in a cell's genes

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The Lock And Key Model

Substrate -  A molecule that is changed in a reaction

Active Site - Part of the enzyme that binds to a protein/substance during a reaction

1. Every enzyme has an ACTIVE SITE 

2. For an enzyme to work, a substrate has to be the correct shape to fit into the active site.

3. This is the Lock and Key Model , because the substrate fits into the enzyme just like a key fits a lock

(http://study.com/cimages/multimages/16/lock_and_key.png)

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Temperature

DENATURED - The substrate no longer fits to the active site so the reaction doesn't take place

OPTIMUM - When the enzymes are most active

"Changing the temperature changes the rate of an enzyme controlled reaction."

STAGES

1. A higher temperature increases the rate AT FIRST

2. If it gets too hot, some of the bonds holding the enzymes together break which changes the shape of the active site and so the substrate doesn't fit which means the enzyme is denatured

(http://www.bbc.co.uk/staticarchive/199acbfe2bac854818d719d6ce0e53e4cd3cd5d2.gif)

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pH

All enzymes have an OPTIMUM pH 

If the pH is too high or low, the active site is changed so the enzyme becomes denatured

The optimum pH for an enzyme is around 8

(http://www.bbc.co.uk/staticarchive/db7ba3135d8cf5ce20b58387bf6b7784436ce279.gif)

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