Term | Definition |
metabolism | the totality of an organism's chemical reactions |
metabolic pathway | begins with a specific molecule and ends with a product |
Catabolic pathway | release energy by breaking down complex molecules into simpler compounds |
anabolic pathway | consumes energy to build complex molecules from simpler ones |
Bioenergetics | the study of how energy flows through living organisms |
Kinetic Energy | energy associated with motion |
Heat (thermal) energy | kinetic energy associated with random movement of atoms or molecules |
Potential Energy | energy that matter possesses because of its location or structure |
Chemical energy | potential energy available for release in a chemical reaction |
Thermodynamics | the study of energy transformations |
Isolated System | unable to exchange energy or matter with its surroundings |
Open System | energy and matter can be transferred between the system and its surroundings |
First Law of Thermodynamics | (principle of conservation of energy) Energy can be transferred and transformed but cannot be created or destroyed. |
Second Law of Thermodynamics | Every energy transfer or transformation increases the entropy (disorder) of the universe |
Entropy | (disorder) entropy may decrease in an organism, but the universe's total entropy increases |
Spontaneous processes | occur without energy input, for this to happen it must increase the entropy of the universe |
Free Energy | measure of a system's instability, tendency to change to a more stable state |
Free Energy Equation | deltaG = deltaH - TdeltaS |
Equilibrium | state of maximum stability |
Exergonic | reaction proceeds with a net release of free energy and is spontaneous |
Endergonic | reaction absorbs free energy from its surroundings and is not spontaneous |
Energy Coupling | the use of an exergonic process to drive an endergonic one |
ATP | ribose sugar + adenine + 3 phosphate groups |
Phosphorylation | transferring a phosphate group to some other molecule |
Phosphorylated intermediate | the recipient molecule of the 3rd phosphate group |
Enzyme | catalytic protein |
Catalyst | a chemical agent that speeds up a reaction without being consumed by the reaction |
Activation Energy | initial energy needed to start a chemical reaction (enzymes lower this barrier to catalyze reactions) |
Substrate | the reactant that an enzyme acts on |
Active site | the region on the enzyme where the substrate binds |
Induced fit | chemical group of the active site in positions that enhance substrate ability to catalyze reactions |
Cofactor | nonprotein enzyme help, can be organic or inorganic |
Coenzyme | organic cofactor |
Competitive Inhibitor | binds to the active site of an enzyme, competing with substrate |
Noncompetitive Inhibitor | binds to another part of an enzyme, causing enzyme to change shape and make active site less effective |
Allosteric Regulation | occurs when a regulatory molecule binds to a protein at one site and affects the proteins function at another site |
Activator | binds to enzyme, stabilizes the active form and stimulates activity |
Inhibitor | binds to enzyme, stabilizes the inactive form |
Cooperativity | form of allosteric regulation that can amplify enzyme activity |
Feedback Inhibition | the end product of a metabolic pathway shuts down the pathway |