Learning Target:Enzymes in Action

Learning Target #1: Enzymes

I Can… Describe the general role of enzymes in metabolic cell processes.

I Will…• Describe the components of metabolic

chemical reactions.• Describe the general characteristics of

enzymes including factors that affect how enzymes work.

Enzymes are the Super Heroes of Homeostasis!

• KEY IDEA: Life depends on chemical reactions

• Metabolism – All the chemical reactions that take place in

your body and cells.Anabolism – joining materials togetherCatabolism – breaking materials apart

Why?

Reactants Yield sign

• Reactants – substances changed during a chemical reaction (Rxn).

• Products – substances made during a chemical Rxn.

Chemical bonds are broken and formed.• Bond energy – energy required to break a bond

between two atoms.

Products

Activation energy – energy that must be absorbed by the reactants before the chemical Rxn can take place.

Endothermic Rxn –• Overall net energy is

absorbed.• Reactants have low

bond energy.• Products have high

bond energy.• More energy must go

into the reaction and is stored in the bonds of the products.

Exothermic Rxn –• Overall net energy is released.• Reactants have high bond energy.• Products have low bond energy.• Excess energy goes out of the

reaction while little is stored in the bonds of the products

Enzymes – catalyst for living things.• Catalyst

Lowers activation energy Is NOT a reactant or a product Is NOT used up or changed in the reaction

CatalystReactants Products• Lowers

activation energy needed

• Increases Rxn rate

Enzymes are specific: Lock-and-Key Model

Substrates/reactants bind to enzyme at active sites (binding sites on enzyme).

Enzyme acts on substrate(s) and weakens bonds (bond energy) Less activation energy needed.

The catalyzed reaction forms a product released from the enzyme.

Denaturing Enzymes

http://www.lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html

• Almost all enzymes are proteins (polypeptide chain)• Shape / folding is maintained by hydrogen bonds• Temperature and pH greatly affect enzymes• Temperatures just slightly above normal body

temp will break the hydrogen bonds

Substrate Enzyme Ratio• Not enough enzyme• Optimal• Too much enzyme