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

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?

Chemical Reactions When bonds are broken and reformed to make different substances, energy is released. EX: Reactants Products C6H12O6 + 6O2 6CO2 + 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.

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 you 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!

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

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

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

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

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

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

Pair up with another set of clock buddies (optional). Demo Time!! Find your 2:00 clock buddy. Pair up with another set of clock buddies (optional). Develop a short play or demonstration that illustrates how enzymes catalyze reactions.

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 somehwere other than the active site, causing a change in shape.

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

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

Pair up with another set of clock buddies (optional). Demo Time!! Find your 2:00 clock buddy. Pair up with another set of clock buddies (optional). Modify your demonstration to include competitive and non- competitive inhibitors.

ATP stores Energy ATP ADP ATP is the special carrier molecule that stores energy available for cell use. ATP energy P Energy from glucose breakdown is stored in ATP Energy in ATP is released to perform cell activities energy Adenosine Triphosphate – three phosphates, and as energy is released a phosphate is broken off. As energy is stored, a phosphate is added. P ADP ATP is the energy currency of the cell; the energy source for all cell functions.