Energy - The ability to do work Needed by all living things There are different forms of energy Light Heat Electrical Sound

Energy for building up – Anabolic Reaction Energy for breaking down – Catabolic Reaction Metabolism is the sum of all anabolic and catabolic reaction in a cell or organism.

All energy can be grouped into either kinetic or potential energy. #1 Kinetic Energy The energy possessed by moving objects ex Thermal (random motion of particles) Mechanical (coordinated motion of particles) Electrical (motion of charged particles)

#2 Potential Energy Stored energy Usually due to position within an attractive or repulsive force field ex gravitational potential energy – the attraction between 2 objects ex chemical potential energy – the attraction of electrons - and protons + in a chemical bond

Thermodynamics – the study of energy transformations in living and non-living systems

First Law of Thermodynamics (Law of Conservation of Energy) Energy cannot be created or destroyed, but only converted from one form to another. The total amount of energy in the universe is constant.

Energy in nature is not always readily available. Organisms must convert it from one form to another. Photosynthesis Sun light energy plants chemical potential energy glucose Cellular respiration glucose energy passed on to ATP (energy-transferring compound in living things)

Bond Energy equals the amount of energy needed to break on mole (6.02 x ) of bonds also a measure of stability of covalent bonds exH-H = 436 kJ/mol C=O = 799 kJ/mol (more stable) In chemical reactions: If reactant bonds broken – energy absorbed If product bonds formed – energy released

Activation Energy: energy needed to strain and break reactant bonds Transitional State: the temporary state where reactant bonds are breaking and product bonds are forming Endothermic / Endergonic Reaction: the energy of the products is higher than the energy of the reactants Exothermic / Exergonic Reaction: the energy of the reactants is higher than the energy of the products

Endothermic / Endergonic Reaction Transition State Products Reactants Net amount of energy gained Activation Energy Chemical Potential Energy Progress of Reaction

Exothermic / Exergonic Reaction Transition State Products Reactants Net amount of energy lost Activation Energy Chemical Potential Energy Progress of Reaction

Entropy – a measure of randomness or disorder of objects or energy Entropy increases when disorder increases.

Entropy increases when: 1. A few number of reactant molecules produce a large number of product molecules 2. Solid reactants become liquid products 3. Liquid reactants become gaseous products