Energy and Matter, Their Laws, and How they are Used in Biological Systems

Matter is Recycled Through Food Chains. Energy Is Not Recycled, It Is Transformed.

Energy : the Capacity to do Work Two Basic Forms of Energy –Kinetic energy is the energy of motion Ex. Muscle contractions and relaxation –Potential energy is stored energy as a result of location or structure and can be used in the future Ex. Top of the hill cyclist

Thermodynamics the Study of Energy Transformations ***Two Laws of Thermodynamics*** –Law of Conservation of Matter Energy can neither be created nor destroyed, it must be transformed from one form to another –Law of Entropy At every transformation of energy from one form to another some energy is converted to heat and lost.

Metabolism: Energy Transformations in Cells The food we eat has chemical bond energy, which is converted into ATP bond energy, then it may be used for the metabolic work of the cell. Some energy is always lost as Entropy (heat).

Metabolism Has Two Types of Chemical Reactions Catabolic Reactions –Break down of large molecules (polymers) into smaller subunits –Products have less energy than reactants –Energy is released, which is converted into ATP, the energy currency of cells –ATP energy may be used for cellular work –EXERGONIC Anabolic Reactions –Building of large molecules from smaller subunits –Products have more energy than the reactants –Energy is consumed during the reaction, usually provided by ATP –ENDERGONIC

Endergonic Reactions are Chemical Reactions that Consume and Store Energy

Exergonic Reactions Chemical Reactions that Release Energy

ATP and Energy Coupling Energy released from exergonic reactions is converted into ATP (phosphate bond) energy and used for powering endergonic reactions in the cell.

Adenosine Tri Phosphate is the Energy Currency in Cells

The Sun is the Ultimate Energy Source, which Maintains Life on the Surface of the Earth Almost all of the chemical energy used by organisms ultimately comes from the sun. Organic matter is recycled through producer/consumer relationships in food webs.