Metabolism Flashcards
An organism's metabolism transforms matter and energy, subject to the laws of thermodynamics. The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously. ATP powers cellular work by coupling exergonic reactions to endergonic reactions. Enzymes speed up metabolic reactions by lowering energy barriers. Regulation of enzyme activity helps control metabolism
Metabolism
The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism
Metabolic Pathway
A series of chemical reaction s that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway)
Catabolic Pathway
A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules
Anabolic Pathway
A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules
Bioenergetics
The overall flow and transformation of energy in an organism
Energy
The capacity to cause change, especially to do work (to move matter against an opposing force)
Thermal Energy
Kinetic energy due to the random motion of atoms and molecules; energy in its most random form
Kinetic Energy
The energy associated with the relative motion of objects. Moving matter can perform work by impacting motion to other matter
Heat
Thermal energy in transfer from one body of matter to another
Potential Energy
The energy that matter possess as a result of its location or spatial arrangement (structure)
Chemical Energy
Energy available in molecules for release in a chemical reaction; a form of potential energy
Thermodynamics
The study of energy transformation that occur 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, or randomness
Second Law of Thermodynamics
The principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat
Spontaneous Process
A process that occurs without an overall input of energy; a process that is energetically favorable
Free Energy
The portion of a biological system’s energy that can perform work when temperature and pressure are uniform throughout the system. The change in this in a system (change in G) is calculated by the equation change in G = change in H - T x change in S, where change in H is the change in enthalpy (in biological systems, equivalent to total energy), change in T is the absolute temperature, and change in S is the change in entropy
Exergonic Reaction
A spontaneous chemical reaction in which there is a net release of free energy
Endergonic Reaction
A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings
Energy Coupling
In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction
ATP (Adenosine Triphosphate)
An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells
Phosphorylated Intermediate
A molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule
Enzyme
A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most are proteins
Catalyst
A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction
