Biology Part. 1 Flashcards
The movement of a substance across a biological membrane against its concentration gradient, aided by specific transport proteins and requiring input of energy (often as ATP).
Active Transport
The part of an enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds); typically, a pocket or groove on the enzyme’s surface.
Active site
Main energy source for cells.
Adenosine triphosphate
A transport protein in the plasma membrane of some plant or animal cells that facilitates the diffusion of water across the membrane (osmosis).
Aquaporin
The aerobic harvesting of energy from food molecules; the energy- releasing chemical breakdown of food molecules, such as glucose, and the storage of potential energy in a form that cells can use to perform work; involves glycolysis, the citric acid cycle, and oxidative phosphorylation (the electron transport chain and chemiosmosis).
Cellular Respiration
Energy available in molecules for release in a chemical reaction; a form of potential energy.
Chemical Energy
An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.
Coenzyme
A nonprotein molecule or ion that is required for the proper functioning of an enzyme. See also coenzyme.
Cofactor
A substance that reduces the activity of an enzyme by binding to the enzyme’s active site in place of the substrate. A competitive inhibitor’s structure mimics that of the enzyme’s substrate.
Competitive Inhibitor
An increase or decrease in the density of a chemical substance in an area.
Concentration Gradient
The spontaneous tendency of a substance to move down its concentration gradient from where it is more concentrated to where it is less concentrated.
Diffusion
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.
Endergonic Reaction
Cellular uptake of molecules or particles via formation of new vesicles from the plasma membrane
Endocytosis
The capacity to perform work, or to rearrange matter.
Energy
In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.
Energy Coupling