Energy- The ability to do work States of Matter - video States of Matter – Solids maintain a fixed volume and shape. molecules move less rapidly than liquids or gases – Liquids maintain a fixed volume, but its particles move more freely than a solid ability to flow and conform to the shape of any container – Gases are composed of particles that move the most. They occupy the space available to them Thermal energy must be added or removed for a substance to change states of matter

Chemical Reaction Chemical Reaction - video when one or more substances change to produce one or more different substances Energy is absorbed or released when chemical bonds are broken or new ones are formed The following is an example of a chemical reaction CO 2 + H 2 O  H 2 CO 3 CO 2 and H 2 O are reactants (found on tail side of the arrow) H 2 CO 3 is the product( found on the head of the arrow)

There are thousands of chemical reactions that occur inside the human body – Reactions that break down food we eat for energy – Reactions that build muscle – Reactions that regulate the amount of sugar in our blood

Oxidation Reduction Reactions – Reactions in which electrons are transferred between atoms…also known as redox reactions Oxidation reactions – a reactant loses one or more electrons, thus becoming more positive Reduction reactions- a reactant gains one or more electrons, thus becoming more negative

Activation energyActivation energy - video the amount of energy needed to start a chemical reaction – Catalysts speed up the rate of the reaction by lowering the amount of activation energy needed to start the reaction – In living things enzymes act as catalysts. – An enzyme is a protein or RNA molecule that speeds up a metabolic reaction without being permanently changed or destroyed

ENZYMES Each type of enzyme catalyzes only ONE or a few specific reactionsenzyme Have an Active Site: region of enzyme that binds to the substrate – groove on protein’s surface that determines specificity – changes its shape in response to the substrate

Substrate Substrate : The substance an enzyme acts on and makes more reactive

Factors that affect Enzyme Activity Enzyme concentration Substrate concentration Temperature Competitive inhibitors pH