1. ENZYMES and Activation Energy
EQ: How do enzymes affect a reaction?
Refer to Enzyme Demo
Ask the students to answer this question.

2. What is Energy?
Energy is the ability to cause matter to move or change.
All life processes are driven by energy
Where does all energy come from?
There are many forms of energy, not all are light. Ex: mechanical, chemical, thermal, nuclear.
Without energy, you do not function.
Energy comes from the sun. – Where have they seen this before?

3. Chemical Reactions
When bonds are broken and reformed to make different substances, energy is released.
EX:
Reactants Products
C6H12O6 + 6O CO2 + 6H2O
Remember, energy is stored in the bonds of the compounds.
Reactants are also called raw materials – They need to know this term.
Have them tell you the reactants and products of the above equation.

4. What is Metabolism?
Metabolism is the sum of all chemical reactions in your body
- Metabolism is basically two components
Breaking down foods for energy
Building new compounds to make new products
Ask the kids what they know about metabolism.
Then show the notes.
Metabolism is the sum of all chemical reactions in your body – it is what allows you to function.
Breaking down foods for energy – breaking the bonds in the compounds
Building new compounds to make you – carbs, lipids, proteins
You are what you eat because the food you eat is broken down and the products are then used to make new compounds. Ex:Hot dog for lunch, body breaks it into monomers (ask them what this term is), then rebuilds the monomers into you. So you are nothing more than recycled hot dog parts!

5. What is needed to start a reaction?
Energy released
Activation energy
Energy absorbed
Activation Energy: energy required to get a reaction started
Point out the high amount of energy needed with reaction in graph.
The activation energy on the graph comes in when you click the mouse – the purpose is to get the answer from them first. – Remember enzyme demo
reactant
Products

6. What is a Catalyst?
A catalyst is anything that lowers activation energy.
Enzymes are organic catalysts.
Predict what the graph will look like after a catalyst (enzyme) is added.
Ask question before notes.
A catalyst is anything that lowers activation energy
They can be organic or inorganic - living or non-living
Organic catalysts are called enzymes

7. What do you notice about the activation energy?
Energy absorbed
Energy released
reactant
Products
Activation energy
Because a catalyst was used.
Catalyst: anything that lowers activation energy
Point out that the amount of energy has been significantly lowered

8. Enzymes lower the amount of activation energy needed
Comparing Reactions
Which line would represent a reaction without an enzyme present?
With an enzyme present?
Energy absorbed
Energy released
Reactant
Products
Enzymes lower the amount of activation energy needed

9. How Do Enzymes Work? Enzymes work like a lock and key.
Specific enzymes have an ACTIVE SITE for specific substrates.
enzyme
Use the analogy of enzymes as a lock and key.
Explain that substrates are reactants.
Substrate (key) must fit exactly into the active site of and enzyme (lock), just like only specific keys fit certain locks.
substrate

10. How Do Enzymes Work? Enzymes are NEVER used up in a reaction!!
Each substrate fits into the enzyme’s active site.
Then the enzyme controls the rate of the chemical reaction.
The substrate is broken into products.
The enzyme is free to accept another substrate.
Enzymes are NEVER used up in a reaction!!
Substrate is also the reactant in a chemical reaction.
Enzymes are not used up in the reaction.
the reaction rate is controlled by enzymes

11. Denaturation
A protein is denatured when it loses its shape and becomes inactive.

12. Enzymes can be affected by:
Temperature:
pH:
Concentration: 3 7 5 9 11 13
Neutral
Battery Acid
Bleach
Blood (7.5)
Temperature: all enzymes have an optimal temp they work best at
pH: acidity/alkalinity can increase or decrease the function of an enzyme
Concentration: Increasing the concentration of the enzyme can increase the rate of the chemical reaction

13. Inhibitors
Competitive Inhibition Occurs when a molecule mimics the substrate and enters the active site, not allowing the real substrate to fit.
Non-competitive Inhibition
Occurs when a molecule binds to an enzyme somewhere other than the active site, causing a change in shape.