All terms in this list:
Fluid mosaic: A description of membrane structure , depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer of phospholipid molecules.
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.
Diffusion: The spontaneous movement of a substance down its concentration gradient from where it is more concentrated to where it is less concentrated.
Concentration gradient/: A region along which the density of a chemical substance increases or decreases. Cells often maintain concentration gradients of ions across their membranes. When a gradient exists, substances tend to move from where they are more concentrated to where th
Passive transport: The diffusion of a substance across a biological membrane, with no expenditure of energy.
Osmosis: The diffusion of water across a selectively permeable membrane.
Tonicity: The ability of a solution surrounding a cell to cause that cell to gain or lose water.
Isotonic: Referring to a solution that, when surrounding a cell, has no effect on the passage of water into or out of the cell.
Hypotonic: Referring to a solution that, when surrounding a cell, will cause the cell to take up water.
Hypertonic: Referring to a solution that, when surrounding a cell, will cause the cell to lose water.
Osmoregulation: The homeostatic maintenance of solute concentrations and the balance of water gain or loss
Facilitated diffusion: The passage of a substance through a specific transport protein across a biological membrane down its concentration gradient.
Active transport: The movement of a substance across a biological membrane against its concentration gradient, aided by specific transport proteins and requiring an input of energy (often as ATP).
Endocytosis: Cellular uptake of molecules or particles via formation of new vesicles from the plasma membrane.
Phagocytosis: Cellular “eating”; a type of endocytosis in which a cell engulfs macromolecules, other cells, or particles into its cytoplasm.
Pinocytosis: Cellular “drinking”; a type of endocytosis in which the cell takes fluid and dissolved solutes into small membranous vesicles.
Receptor-medicated endocytosis: The movement of specific molecules into a cell by the inward budding of membranous vesicles, which contain proteins with receptor sites specific to the molecules being taken in.
Energy: The capacity to cause change, especially to perform work.
Kinetic energy: The energy of motion; the energy of a mass matter that is moving. Moving matter does work by imparting motion to other matter.
Heat: Thermal energy; the amount of energy associated with the movement of the atoms and molecules in a body of matter.
Potential energy: The energy that matter possess because of its location or arrangement
Chemical energy: Energy available in molecules for release in a chemical reaction; a form of potential energy.
Thermodynamics: The study of energy transformation that occurs in a collection of matter.
First law of thermodynamics: The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.
Entropy: A measure of disorder. One form of disorder is heat, which is random molecular motion.
Second law of thermodynamics: The principle stating that every energy conversion reduces the order of the universe, increasing its entropy. Ordered forms of energy
Second law of thermodynamics: The principle stating that every energy conversion reduces the order of the universe, increasing its entropy. Ordered forms of energy are at least partly converted to heat.
Cellular respiration: Theaerobicharvesting ofenergyfrom foodmoleculesthe energyreleasingchemicalbreakdown offood molecules such as glucoseandthestorageofpotential energy in a form that cells can use to perform workinvolves glycolysis the citric acid cycle
Exergonic reaction: 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.
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.
Metabolism: The totality of an organisms chemical reactions
Metabolic pathway: A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds
Energy coupling: In a cellular metabolism, the use of energy released from a exergonic reaction to drive an endergonic reaction.
ATP: Adenosine triphosphate, the main energy source for cells.
Phosphorylation: The production of ATP by chemiosmosis during the light reactions of photosynthesis.
Activation energy: The amount of energy that reactants must absorb before a chemical reaction will start.
Enzymes: A macromolecule, usually a protein that serves as a biological catalyst, changing the rate of a chemical reaction without being consumed by the reaction.
Substrate: A specific substance (reactant)on which an enzyme acts.
Active site: The part of an enzyme molecule where a substrate molecule attaches (by means of a weak chemical bond); typically a pocket or groove on the enzymes surface.
Induced fit: The change in shape of the active site of an enzyme, caused by entry of the substrate, so that it binds more snugly to the substrate.
Cofactor: A non-protein molecule or ion that is required for the proper functioning of an enzyme.
Coenzyme: An organic molecule serving as a cofactor.
Competitive inhibitor: A substance 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 reduces the activity of an enzyme without entering an active site.
Feedback inhibiton: A method of metabolic control in which a
Feedback inhibiton: A method of metabolic control in which a product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.