section2.5enzymes.notebook
September 11, 2015
Activation Energy and Catalyst
Activation energy is the energy needed to start a chemical reaction.
Once the reaction starts it may happen very slowly.
This causes an increase in temperature.
A catalyst decreases the activation energy and increases the rate of chemical reaction.
Less energy is needed and products form faster!
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section2.5enzymes.notebook
September 11, 2015
Enzymes
­catalysts for chemical reactions in living things
­ used in digestion, building proteins, immune system and many more
­Most enzymes are proteins
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section2.5enzymes.notebook
September 11, 2015
Structure and Function
­Substrates­ what the enzyme breaks down
­example ­amylase in your saliva only breaks down starches
How they work:
1. substrates bind with the enzymes
2. the enzyme brings the substrates together and weakens their bonds.
3. The product is released.
­Enzyme is unaffected
This is called the lock and key model. Only certain keys fit in certain locks.
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section2.5enzymes.notebook
September 11, 2015
Affects of Conditions
Enzymes only function under certain conditions.
­pH­different for different areas of the body
­Temperature­ high fevers very dangerous
­Salinity
­Concentration of substrate
all affect the function
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