| A | B |
|---|
| Metabolism | Totality of an organism's chemical processes. |
| Catabolic pathway | Metabolic pathways that release energy by breaking down complex molecules into simple ones. |
| Anabolic pathway | Pathway that consumes energy to build complicated molecules from simpler ones. |
| Energy | Capacity to do work. |
| Kinetic energy | Energy in the process of doing work. Energy of motion. |
| Potential energy | Energy that matter possesses because of its location or arrangement (Energy of position or condition.) |
| Thermodynamics | Study of energy transformations. |
| First Law of Thermodynamics | Energy can be transferred and transformed, but it cannot be created or destroyed. |
| Second Law of Thermodynamics | Every energy transfer or transformation makes the universe more disordered (every process increases the entropy of the universe.) |
| Entropy | Quantitative measure of disorder that is proportional to randomness. |
| Closed system | Collection of matter under study which is isolated from its surroundings. |
| Open system | System in which energy can be transferred between the system and its surroundings. |
| Spontaneous reaction | A reaction that will occur without additional energy. |
| Exergonic reaction | A reaction that proceeds with a net loss of free energy. |
| Endergonic reaction | An energy-requiring reaction that proceeds with a net gain of free energy. |
| ATP | A nucleotide with unstable phosphate bonds that the cell hydrolyzes for energy to drive endergonic reactions. |
| Phosphorylation | The addition of a phosphate group to a molecule making it more reactive. |
| Catalyst | Chemical agent that accelerates a reaction without being permanently changed in the process. |
| Enzyme | Biological catalyst usually made of protein. |
| Activation energy | Amount of energy that reactant molecules must absorb to start a reaction. |
| Transition state | Unstable condition of reactant molecules that have absorbed sufficient free energy to react. |
| Substrate | The substance an enzyme acts on and makes more reactive. |
| Active site | Restricted region of an enzyme molecule which binds to the substrate. |
| Induced fit | Change in the shape of an enzyme's active site, which is induced by the substrate. |
| Cofactor | A small nonprotein molecule that is required for proper enzyme catalysis. |
| Coenzyme | An organic cofactor. |
| Competitive inhibitor | Chemical that resembles an enzyme's normal substrate and competes with it for the active site. |
| Noncompetitive inhibitor | Enzyme inhibitor that does not enter the enzyme's active site, but binds to another part of the enzyme molecule. |
| Allosteric site | Specific receptor site on some part of the enzyme molecule other than the active site. |
| Feedback inhibition | Regulation of a metabolic pathway by its end product, which inhibits an enzyme within the pathway. |
| Activator | Molecule which binds to an allosteric site and stabilizes the active conformation. |
| Inhibitor | Molecule that binds to the allosteric site of an enzyme and stabilizes the inactive conformation. |
