| A | B |
|---|
| Energy | the capacity to perform work |
| Kinetic energy | energy that is actually doing the work |
| Heat | energy associated with the movement of molecules in a body of matter |
| Potential energy | capacity to perfoem work that matter possesses as a result of it's location or arrangement |
| Chemical energy | potential energy of molecules; most important for living organisms |
| Thermodynamics | study of energy transformaitons that occur in a collection of matter |
| First Law of Thermodynamics | (law of energy conservation) total amount of energy in the universe is constant |
| Second Law of Thermodynamics | energy conversions reduce the order of the universe |
| Entropy | amount of disorder in a system |
| Endergonic reactions | An energy-requiring chemical reaction, which yields products with more potential energy than the reactants. The amount of energy stored in the products equals the difference between the potential energy in the reactants and that in the products. |
| Exergonic reactions | An energy-releasing chemical reaction in which the reactants contain more potential energy than the products. The reaction releases an amount of energy equal to the difference in potential energy between the reactants and the products. |
| Cellular respiration | energy-releasing chemical breakdown of glucose molecules and the storage of of the energy in a form that the cell can use to perform work |
| Cellular metabolism | The chemical activites of cells. |
| Energy coupling | using energy released from exergonic reactions to drive essential endergonic reactions |
| Phosphorylation | transfer of a phosphate group to a molecule |
| Energy of Activation | The amount of energy that reactants must absorb before a chemical reaction will start. |
| Enzyme | A protein molecule that serves as a biological catalyst, increasing the rate of a reaction without itself being changed into a different molecule. |
| Substrate | A specific substance (reactant) on which an enzyme acts. Each enzyme recognizes only the specific substrate or substrates of the reaction it catalyzes. |
| Active site | small part of an enzyme which actually binds to the substrate |
| Cofactors | A non-protein substance that helps an enzyme catalyze a metabolic reaction. |
| Coenzymes | An organic substance that acts as a cofactor, helping an enzyme catalyze a metabolic reaction. |
| Competitive inhibitor | A substance that reduces that reduces the activity of an enzyme by binding to the enzyme's active site in place of the substrate. |
| Noncompetitive inhibitor | A substance that impedes the activity of an enzyme without entering an active site; by binding elsewhere on the enzyme, it changes the shape of the enzyme so that the active site no longer functions. |
| Negative feedback | A control mechanism in which a chemical reaction, metabolic pathway, or hormone-secreting gland is inhibited by the products of the reaction, pathway, or gland. |
| Selective permeability | A property of biological membranes that allows some substances to cross more easily than others and blocks the passage of other substances altogether. |
| Fluid mosaic | A description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer made of phospholipid molecules. |
| Signal transduction | In cell biology, a series of molecular changes that converts a signal on a target cell's surface into a specific response inside the cell. |
| Receptors | On or in a cell, a specific protein molecule whose shape fits that of a specific molecular messenger, such as a hormone. |
| Diffusion | The tendency of particles of any kind to spread out spontaneously from where they are more concentrated to where they are less concentrated; teh tendency of molecular order to become disordered. |
| Passive transport | The diffusion of a substance across a biological membrane, without the cell's performing any work. |
| Concentration gradient | A regular increase/decrease in the intensity or density of a chemical substance. |
| Osmosis | The movement of water across a selectively permeable membrane. |
| Hypertonic solution | In comparing two solutions, the one with the greater concentration of solutes. |
| Isotonic solution | A solution having the same solute concentration as another solution. |
| Osmoregulation | The control of the gain and loss of water and dissolved solutes in an organism. |
| Facilitated diffusion | The passage of a substance across a biological membrane down its concentration gradient, aided by specific transport proteins. |
| Active transport | The movement of a substance across a biological membrane against its concentration gradient, aided by specific transport proteins and requiring cellular work. |
| Exocytosis | The movement of materials out of the cytoplasm of a cell via membranous vesicles or vacuoles. |
| Endocytosis | The movement of materials into the cytoplasm of a cell via membranous vesicles or vacuoles. |
| Phagocytosis | Cellular "eating", a type of endocytosis whereby a cell engulfs macromolecules, other cells, or particles into it's cytoplasm. |
| Pinocytosis | Cellular drinking; a type of endocytosis whereby the cell takes fluid and dissolved solutes into small membranous vesicles. |
| Receptor-mediated endocytosis | The movement of specific molecules into a cell by the inward budding of membranous vesicles. The vesicles contain proteins with receptor sites specific to the molecules being taken in. |
| Hypercholesterolemia | An inherited human disease characterized by an excessively high level of cholesterol in the blood. |
