Flashcards in Chapter 6 - Energy & Metabolism Deck (31):
Amount of work a thermodynamic system can perform. The internal energy of a system minus the amount of energy that cannot be used to perform work.
A chemical reaction in which the standard change in free energy is positive, and energy is absorbed.
A reaction where energy is released. Because the reactants lose energy (G decreases), Gibbs free energy (ΔG) is negative under constant temperature and pressure. These reactions usually do not require energy to proceed, and therefore occur spontaneously.
Releases free energy (usually as heat) and moves to a lower, more thermodynamically stable energy state. When ΔG is negative, a process or chemical reaction proceeds spontaneously in the forward direction.
Chemical reactions are reversible, therefore an exergonic reaction moving in a forward direction will be endergonic in reverse direction. For each reaction, an equilbrium exists. This numerical value is the EC.
Extra energy needed to destabilized existing chemical bonds and initiate a chemical reaction.
The substrates that influence chemical bonds in a way that lowers the activation energy needed to initiate a reaction.
Adonisine triphosphate; composed of three smaller components: a five-carbon sugar (ribose), an organic molecule composed of two carbon-nitrogen rings (adenine), and a chain of three phosphates (triphosphate). Stores energy in triphosphates
Stores energy in triphosphate group. When unstable bonds are broken by hydrolysis, energy is released.
When outermost high energy phosphate bond is hydrolyzed, phosphate group is cleaved off the end and becomes ADP (adonisine diphosphate).
Protein that is capable of speeding up the specific chemical reactions by lowering the required activation energy.
Complex formed when an enzyme binds with its substrate. Often has an altered configuration compared with non-bound enzyme.
Enzyme substrate complex
Foundation to which an organism is attached.
Region of an enzyme surface to which a specific set of substrates binds, lowering the activation energy required for a particular chemical reaction and so facilitating it.
When an enzyme binds to the appropriate substrate, subtle changes in the active site occur. Enhances catalysis, as the enzyme converts substrate to product.
Assembly consisting of several enzymes catalyzing different steps in a sequence of reactions. Close proximity speeds process and makes more efficient.
RNA molecule that can behave as an enzyme, sometimes catalyzing its own assembly; rRNA also acts as one in polymerization of amino acids to form protein.
Substance that binds to an enzyme and decreases its activity.
Compete with the substrate for the same active site, occupying the active site and preventing substrates from biding.
Bind to the enzyme in a location other that the active site, changing the shape of the enzyme and making it unable to bind to a substrate.
Enzymes that can exist in either active or inactive conformation.
Where noncompetative inhibitors bind to a specific portion of the enzyme.
Substance that binds to an allosteric site and reduces enzyme activity.
Binds to allosteric sites to keep an enzyme in its active configuration, thereby increasing enzyme activity.
Assist enzyme functions. Can be metal ions that participate in catalysis.
(eg: zinc and protein digestion)
When a cofactor is a nonprotein organic molecule.
(eg: B vitamins, modified nucleotides)
Total of all chemical reactions by an organism.
Chemical reactions that expend energy to build up molecules.
Reactions that harvest energy by breaking down molecules.
Product of one chemical reaction becomes substrate for the next. Organizational units of metabolism.