chapter 5.5 enzymes are proteins that speed up specific reactions in cells
Post on 30-Dec-2015
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ENZYMES AND ACTIVATION ENERGY
• Activation Energy- the energy needed to start a reaction
• EXAMPLE: Candle Burning• If you heat something to lower the activation
energy structures in the cell can become destroyed
• Therefore, we need enzymes!
ENZYMES AND ACTIVATION ENERGY
• Catalysts- substances that speed up chemical reactions
• Enzyme- the main catalyst of chemical reactions
What are enzymes?
• Your body has lots of reactions!
• Enzymes: Special Proteins that speed up specific reactions
• End in ASE – Ex. Lactase digest lactose
• HOW?
Lower the Activation Energy
• Activation energy is the “start up” energy of a reaction
• Enzymes speed up reactions by lowering the activation energy
• They do not raise the temp!
8
Enzymes
FreeEnergy
Progress of the reaction
Reactants
Products
Free energy of activation
Without EnzymeWith Enzyme
Elephant Toothpaste
• http://www.youtube.com/watch?v=7qtX6XgDeDY
HOW ENZYMES WORKEnzymes are Specific
• The shape of an enzyme fits only particular molecules
• Substrate- a specific reactant to an enzyme
• Active Site- the area the substrate fits in
Enzymes
http://www.youtube.com/watch?v=hoBhOdQV7vw
Enzymes are Reusable
• Enzymes will speed the reaction for a substrate
• It will release the product and will work on another substrate
Examples
• Lipase • Protease • Lactase • Sucrase • Amylase
• Life is not possible without enzymes! !!!!!!!
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