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Unformatted text preview: CHAPTER 6 Energy the capacity to do work- Work what occurs when a force operates on an object over a distance- Rather, the capacity for change- Metabolic reactions and catalysts are essential to the biochemical transformation of energy by living things o Transformation of energy is a hallmark of life- Energy can neither be created nor destroyed, only transformed from one type to another o Energy transformations are linked to the chemical transformations that occur in cells the breaking of chemical bonds, the movement of substances across membranes, etc There are two basic types of energy and metabolism- Energy comes in all forms (chemical, electric, heat, light, mechanical) but can be divided into two main categories potential and kinetic o Potential energy energy of state or position Stored energy Can be stored in many forms chemical bonds, concentration gradient, electrical charge imbalance, etc) o Kinetic energy energy of movement Energy that does work potential energy stored in taut muscles is converted into muscle contractions- Potential and kinetic energy can interconvert, as can the form (chemical to mechanical, etc)- Metabolism sum total of these reactions, two types of metabolic reactions occus in all cells of all organisms: anabolic and catabolic o Anabolic reactions (anabolism) link simple molecules to form more complex molecules Building, synthesis Require an input of energy, and capture it in the chemical bonds that are formed o Catabolic reactions (catabolism) break down complex molecules into simpler ones Release the energy stored in the chemical bonds- Catabolic and anabolic reactions are often linked First law of thermodynamics: Energy is neither created nor destroyed- In any conversion of energy from one form to another, the total energy before and after the conversion is the same Second law of thermodynamics: disorder tends to increase- When energy is converted from one form into another, some of that energy becomes unavailable to do work o No physical process or chemical reaction is 100% efficient not all of the energy released can be converted into work o Some energy is lost to disorder o Disorder a kind of randomness o Takes energy to impose order on a system unless energy is applied to impose order on a system, that system will be randomly arranged or disordered- Not all energy can be used o Total energy = usable energy + unusable energy o Total energy enthalpy (H) o Usable energy that can do work free energy (G) o Unusable energy...
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This note was uploaded on 08/10/2010 for the course BIS 2A BIS 2A taught by Professor Gerhart during the Spring '10 term at UC Davis.
- Spring '10