Learn: Biology Energy and Metabolism: Thermodynamics, ATP, and Enzymes

• Kinetic energy

Energy of motion.

• Potential energy

Stored energy based on position or structure.

• First law of thermodynamics

Energy cannot be created or destroyed, only transformed.

• Second law of thermodynamics

Energy transfers increase the universe's entropy (disorder).

• Entropy

A measure of disorder or randomness.

• Spontaneous change

A process that occurs without a continuous input of energy.

• Free energy

Usable energy available to do work.

• Bond energy

Energy required to break a chemical bond.

• Mole

A unit measuring \(6.02 \times 10^{23}\) particles of a substance.

• Activation energy (\(E_{a}\))

Minimum energy needed to start a reaction.

• Transition state

An unstable, high-energy state during a reaction.

• Exothermic reaction

A reaction that releases heat.

• Endothermic reaction

A reaction that absorbs heat.

• Exergonic reaction

A spontaneous reaction that releases net free energy.

• Endergonic reaction

A non-spontaneous reaction that absorbs net free energy.

• Metabolism

Total chemical reactions in an organism.

• Catabolic pathway

Breaks down complex molecules and releases energy.

• Anabolic pathway

Consumes energy to build complex molecules.

• Energy coupling

Using energy from an exergonic reaction to drive an endergonic one.

• Phosphorylation

Adding a phosphate group to a molecule.

• ATP cycle

The continuous breakdown and regeneration of ATP.

• Dehydrogenase

An enzyme that removes hydrogen atoms (electrons) during oxidation.

• NADH

An electron carrier molecule that transports high-energy electrons.