Metabolic Processes and Thermodynamics

A set of vocabulary flashcards covering key terms and definitions related to metabolic processes and thermodynamics.

Metabolism

The sum of all anabolic and catabolic reactions that occur in a cell.

Anabolism

Constructive metabolic processes in which cells build larger molecules from smaller ones.

Catabolism

Deconstructive metabolic processes in which cells break down larger molecules into smaller ones.

Bond Energy

The amount of energy needed to break a bond, equal to the energy released when the bond is formed.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Enthalpy (H)

The total energy content of a system, measured under constant pressure.

Exothermic Reaction

A reaction that releases heat energy to the surroundings.

Endothermic Reaction

A reaction that absorbs heat energy from the surroundings.

Entropy (S)

A measure of the disorder or randomness in a system.

Second Law of Thermodynamics

Entropy in an isolated system always increases over time.

ΔH

The change in enthalpy, or the net energy absorbed or released in a reaction.

ΔS

The change in entropy, representing the difference between the final and initial states of a system.

Spontaneous Reaction

A reaction that occurs naturally without external influence.

Gibb's Free Energy (ΔG)

The energy available to do work in a system, calculated as ΔG = ΔH - TΔS.

Endergonic Reaction

A reaction in which free energy increases, not spontaneous, ΔG > 0.

Exergonic Reaction

A reaction in which free energy decreases, spontaneous, ΔG < 0.

Cellular Metabolism

The chemical processes that occur within a cell to maintain life, including respiration.

Electron Carriers

Molecules that transport electrons during redox reactions in cellular respiration.

NAD+

Nicotinamide adenine dinucleotide, an electron carrier that accepts electrons to form NADH.

FAD

Flavin adenine dinucleotide, an electron carrier that accepts electrons to form FADH2.

ATP (Adenosine Triphosphate)

The primary energy carrier in all living organisms.

ATP Hydrolysis

The breakdown of ATP into ADP and inorganic phosphate, releasing energy.

ADP (Adenosine Diphosphate)

A nucleotide that is formed when ATP loses a phosphate group, releasing energy.

Photosynthesis

An anabolic reaction that converts light energy into chemical energy by creating glucose.

Cellular Respiration

A catabolic reaction that breaks down glucose to release energy.

OILRIG

A mnemonic for oxidation is loss, reduction is gain (referring to electrons).

LEO the lions goes GER

A mnemonic indicating that losing electrons means oxidation and gaining electrons means reduction.

Activation Energy

The minimum energy required for a chemical reaction to occur.

Cyclic Pathway

A series of chemical reactions in which products of one reaction are reactants of another.

Chemical Equilibrium

The state in which the forward and reverse reaction rates are equal.

Sublimation

The process in which a solid transitions directly to a gas without passing through a liquid state.

Diffusion

The movement of particles from an area of high concentration to an area of low concentration.

Thermal Energy

The total kinetic energy of particles in a substance.

Potential Energy

Stored energy depending on the position or arrangement of an object.

Kinetic Energy

Energy of motion.

Coupling Reactions

Linking exergonic reactions with endergonic reactions to drive biological processes.

Free Energy Change

The energy difference between reactants and products in a chemical reaction.

Hydrolysis Reaction

A chemical reaction that breaks down compounds by adding water.

Temperature Effect on Entropy

Increasing temperature typically increases the entropy of a system.

Randomness Measure

Entropy quantifies the level of disorder in a system.

Energetic Preference

Systems tend to favor states of higher entropy.