Unit 4: Enzymes and Energy

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 reactions 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

energy

the capacity to cause change, especially to do work (to move matter against an opposing force)

kinetic energy

the energy associated with the relative motion of objects; moving matter can perform work by imparting motion to other matter

thermal energy

kinetic energy due to the random motion of atoms and molecules; energy in its most random form; thermal energy in transfer from one body to another

potential energy

the energy that matter possesses 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

adenosine triphosphate ( ATP)

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.

free energy

the portion of a biological system’s energy that can perform work when temperature and pressure are uniform throughout the system

exergonic

a spontaneous chemical reaction in which there is a net release of free energy

endergonic

a nonspontaneous 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

ΔG

the change in free energy of a system

spontaneous

a process that occurs without an overall input of energy; a process that is energetically favorable

nonspontaneous

a process that occurs with an overall input of energy