Chapter 6 - Making Life Work: Capturing And Using Energy Flashcards
The energy of motion
Kinetic Energy
Stored energy that is released by a change in an object’s structure or position
Potential Energy
The law of conservation of energy: Energy can neither be created nor destroyed- it can only be transformed from one form into another
First Law of Thermodynamics
The principle that the transformation of energy is associated with an increase in the degree of disorder in the universe
Second Law of Thermodynamics
The degree of disorder in a system
Entropy (S)
The amount of energy available to do work
Gibbs Free Energy (G)
Describes reactions with a negative 🔼G that release energy and proceed spontaneously
Exergonic
Describes reactions with a positive 🔼G that are not spontaneous and so require an input on energy
Endergonic
The total amount of energy in a system
Enthalpy (H)
Temperature measure on the Kelvin scale
Absolute Temperature (T)
The driving of a non-spontaneous reaction by a spontaneous reaction
Energetic coupling
A protein that functions as a catalyst to accelerate the rate of a chemical reaction; enzymes are critical in determining which chemical reactions take place in a cell
Enzyme
The brief time in a chemical reaction in which chemical bonds in the reactants are broken and new bonds in the product are formed
Transition State
The energy input necessary to reach the transition state
Activation Energy (EA)
A molecule acted upon by an enzyme
Substrate (S)
The portion of the enzyme that binds substrate and concerts it to product
Active Site
Any one of a class of inhibitors that usually forms covalent bonds with enzymes and irreversibly inactivated them
Irreversible Inhibitors
Any molecule in the class of inhibitors that form weak bonds with enzymes and easily dissociate from them
Reversible Inhibitors
A reversible inhibitor that reduces the affinity of the substrate for the active site of an enzyme, but can be overcome by excess substrate so the maximum velocity of the reaction is not changed. Competitive inhibitors usually have a structure similar to that of the substrate and therefore bind to the active site of the enzyme
Competitive Inhibitor
A reversible inhibitor that reduces the maximum velocity of the reaction, but does not affect the affinity of the substrate for the active site of the enzyme. It usually has a structure very different from that of the substrate and binds to the enzyme at a site different from the active site
Non-competitive Inhibitor
Describes the effect in which the final product of a biochemical pathway inhibits the first step; the process in which a stimulus acts on a sensor that communicates with an effective, producing a response that opposes the initial stimulus. Negative feedback is used to maintain steady conditions, or homeostasis
Negative Feedback
An enzyme whose activity is affected by binding a molecule at a site other than the active site. Typically, also steric enzymes change their shape on binding an activator or inhibitor
Allosteric Enzyme
A substance that associates with an enzyme and plays a key role in its function
Cofactors
The molecule that provides energy in a form that all cells can readily use to perform the work of the cell. ATP is the universal energy currency for all cells.
Adenosine triphosphate (ATP)
