Understanding Gibbs Free Energy and Enzyme Function

Gibb's Free Energy (G)

Usable energy needed for cellular reactions.

Entropy (S)

Unusable energy lost to disorder.

Enthalpy (H)

Total energy in a system.

ΔG

Change in usable energy for a reaction.

Endergonic Reactions

Reactions requiring energy input, ΔG positive.

Exergonic Reactions

Reactions releasing energy, ΔG negative.

Activation Energy

Energy required to initiate a reaction.

Transition State Intermediates

Unstable state of reactants during a reaction.

Enzyme-Substrate Complex

Formation of enzyme binding to substrate.

Induced Fit

Enzyme shape change after substrate binding.

Inhibitors

Substances that reduce enzyme activity.

Allosteric Regulators

Bind away from active site, altering enzyme shape.

Irreversible Inhibitors

Covalently bind to enzymes, permanently disabling them.

Reversible Inhibitors

Non-covalently bind, allowing enzyme function to resume.

Competitive Inhibitors

Compete with substrate for active site binding.

Noncompetitive Inhibitors

Bind elsewhere, altering enzyme's active site shape.

Feedback Inhibition

Final product inhibits first enzyme in pathway.

Anabolic Reactions

Building reactions, typically endergonic.

Catabolic Reactions

Breaking down reactions, typically exergonic.

Hydrolysis Reaction

Breaking bonds to release energy.

Kinetic Energy

Energy of motion, enabling transition state entry.

Metabolic Pathways

Series of reactions catalyzed by different enzymes.

Caloric Measurement

Energy measured in calories (cal) or joules (J).

Molecular Motion

Random movement of atoms and molecules.