AP Bio 8a Vocab

1st law of thermodynamics

The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed.

2nd 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.

anabolic pathway

A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules.

catabolic pathway

A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules.

chemical energy

Energy available in molecules for release in a chemical reaction; a form of potential energy.

endergonic reaction

A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings.

energy

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

entropy

A measure of molecular disorder, or randomness.

exergonic reaction

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

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 free energy of a system (delta *G*) is calculated by taking the change in enthalphy (delta *H*) and subtracting the product of the temperature (*T*) and the change in entropy (delta *S*). In biological systems, the change in enthalphy is equivalent to total energy, and the change in temperature is the absolute temperature.

heat/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 of matter to another.

isolated system

A system in which no matter or energy is being exchanged with the surroundings

kinetic energy

The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter.

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).

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.

nonspontaneous process

process that will not take place unless it is “driven” by the continual input of energy from an external source

open system

One in which energy can be transferred between the system and its surroundings.

potential energy

The energy that matter possesses as a result of its location or spatial arrangement (structure).

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spontaneous process

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

thermodynamics

The study of energy transformations that occur in a collection of matter; The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed and 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.