Period 4 11/17/16
Chapter 8.1 Notes EQ: What Physical Principles Underlie Biological Energy Transformations?
What is the difference between potential energy and kinetic energy? Between anabolism and catabolism?
What are laws of thermodynamics? How do they relate to biology?
-Metabolic reactions and catalysts are essential to the biochemical transformation of energy by living things. In biochemistry, it is more useful to consider energy as the capacity for change. There are two basic types of energy and of metabolism -Energy comes in many forms: chemical, electrical, heat, light, and mechanical. But all forms of energy can be considered as 1 of 2 basic types: • Potential energy is the energy of state or position—that is, stored energy. Can be stored in many forms: in chemical (Figure 8.1) b onds, as a concentration gradient, or even as an electric charge imbalance • Kinetic energy is the energy of movement—that is, the type of energy that does work, that makes things change. -Chemical reactions continuously occur in the body to provide energy and the totality of these reactions is called metabolism. • Anabolic reactions (anabolism) link simple molecules to form more complex molecules. Anabolic reactions require an input of energy and capture it in the chemical bonds that are formed. • Catabolic reactions (catabolism) break down complex molecules into simpler ones and release the energy stored in chemical bonds. -Catabolic & anabolic reactions are often linked. -The laws of thermodynamics (“energy”; dynamics, “change”) were derived from studies of the fundamental physical properties of energy, and the ways it interacts with matter. The first law of thermodynamics: Energy is neither created nor destroyed -The first law of thermodynamics states that in any conversion of energy, it is neither created nor destroyed. Another way of saying this is: in any conversion of energy, the total energy before and after the conversion is the same. (Figure 8.2) The second law of thermodynamics: Disorder tends to increase -Although energy cannot be created or destroyed, the second law of thermodynamics states that when energy is converted from one form to another, some of that energy becomes unavailable for doing work. -It takes energy to impose order on a system. Unless energy is applied to a system, it will be randomly arranged or disordered. -NOT ALL ENERGY CAN BE USED In any system, the total energy includes the usable energy that can do work and the unusable energy that is lost to disorder: