Enzymes Biological catalysts 18.11-Explain the role of enzymes as catalysts that lower the activation energy of biochemical reactions. Identify factors such as pH and temperature, and their effect on enzyme activity.

Enzymes Objective: Investigate and report factors (e.g. surface area, pH, catalysts, and temperature) that affect the rate of reaction among atoms and molecules EQ: How do different environmental factors affect enzyme activity?

Chemical Reactions A chemical reaction changes the original substances (chemicals) into new, different substances Bonds break and form Reactants: the compounds that you begin with; substances that are changed by the reaction On the LEFT side of a reaction equation Products: the compounds that you end with (what the reaction produces) *think math* On the RIGHT side of a reaction equation

Chemical Reactions Photosynthesis is a chemical reaction 6 CO2 + 6 H2O  C6H12O6 + 6 O2 Which compounds are products and which are reactants? direction

Photosynthesis is a chemical reaction 6 CO2+ 6 H2O  C6H12O6 + 6 O2 Chemical Reactions Photosynthesis is a chemical reaction 6 CO2+ 6 H2O  C6H12O6 + 6 O2 direction Products (what we end with) Reactants (what we started with)

Activation Energy Activation Energy: the energy required for a reaction to begin Like the energy needed to push a ball up a hill; once at the top, the ball will roll down the other side of the hill on its own

Types of Reactions Exothermic: overall, energy is released by the reaction Extra energy given off as heat, light, etc.

Types of Reactions Endothermic: overall, energy is absorbed by the reaction The reaction will feel cold

Check for Understanding Identify the reaction as endothermic or exothermic. Exothermic!

Check for Understanding Identify the reaction as endothermic or exothermic. Endothermic!

Check for Understanding Identify the reaction as endothermic or exothermic. Exothermic!

Check for Understanding Just for fun…

Catalysts Catalyst is reuseable! (not changes by the reaction) A catalyst is a substance that speeds up the rate of a chemical reaction by lowering the activation energy Catalyst is reuseable! (not changes by the reaction)

Enzymes act as biological catalysts Enzymes are catalysts in living things. Catalase is the enzyme that catalyses the break down of hydrogen peroxide. Catalase

hydrogen peroxide water + oxygen 2H2O2 2H2O + O2 Hydrogen peroxide breaks down to water and oxygen hydrogen peroxide manganese oxide water + oxygen 2H2O2 2H2O + O2 The escaping oxygen causes the foaming

Enzyme Lab Honors What is the purpose of the lab? What reaction are we observing? What enzyme are we using? What are you testing in each part of the lab?

Enzyme Lab Working in groups, you will complete the lab to see the affects of temperature, pH, and concentration on enzyme activity. C- level 2 voices H- ask your lab group, then raise a silent hand A- complete enzyme investigation M- remain at your assigned lab table until complete, then clean up once you’re done & take your assigned table seat P- work with your group to collect data but each member of the team must turn in their own copy SUCCESS!

Enzyme Lab Review What is the affect of concentration on enzyme reaction rate? How do you know based on your results? What is the effect of Temperature on enzyme reaction rate? How do you know based on your results? What is the affect of pH on enzyme activity? How do you know based on your results?

What factors affect enzyme activity? Exit ticket Clear your desk What factors affect enzyme activity?