1. 2-4 Chemical Reactions and Enzymes

2. Chemical Reactions
Process of changing one set of chemicals into another set of chemicals
Demonstration:
Reactants (what enters a reaction) Products (what is produced)
H2O + CO2 + sunlight → C6H12O6 + O2
water + carbon dioxide + sunlight → glucose (sugar) and
oxygen
Notice: Chemical reactions involve changes in chemical BONDS
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3. Energy Reactions
Some chemical reactions release energy and others absorb
Chemical reactions that release often occur spontaneously
Reactions that absorb energy will not occur without a source of energy
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4. http://sisnet. ssku. k12. ca
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5. Chemical Reactions Activation energy – energy needed to get a reaction
going.
Energy-Absorbing Reaction
Energy-Releasing Reaction
Sugar + O2
Products
Activation
energy
sunlight
Sugar + O2
Activation energy
CO2 + H20
Reactants
CO2 + H2O
Reactants
Products
Won’t occur without constant
source of energy
Occur spontaneously or with a little
“boost”
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6. Enzymes
Catalyst – substance that speed up chemical reactions. The MATCH
Enzyme – Protein. Biological Catalyst. Used in cells to speed up chemical reactions. We can’t have a MATCH in our bodies. We would overheat!!!
Cells use enzymes to speed up chemical reaction by lowering the amount of activation energy needed to get the reaction
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7. http://videos. howstuffworks
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9. Enzyme Action Reactants (could be food you eat) Lock and key
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