Lecture 4 - Lecture 4 Cell Functions What is energy Capacity to do work Kinetic-the energy of motion-Photons large objects Potential-Stored

Lecture 4 – Cell Functions What is energy? Capacity to do work Kinetic -the energy of motion ---Photons large objects Potential -Stored energy ---Chemical of mechanical The laws of thermodynamics describe the basic properties of energy -The total energy in a given system remains constant, never created or destroyed -When energy is converted from one form to another, the total amount of useful energy decreases. Conservation of Energy -Laws of thermodynamics can be stated as the principle of conservation of energy ---Energy can never be created or destroyed, only converted from one form to another. Entropy If energy can’t be created or destroyed, what happens to it? -Converted to heat! ---Heat is the kinetic energy contained in the random movement of atoms and molecules ---Entropy is a measure of disorder of molecules (or “randomness”) and increases when energy changes form Chemical Energy -Potential energy contained in molecules of fuel -Carbs and fats (like gasoline) are rich in chemical energy Calories