Biology Week 11 Lecture 28: Enzyme Regulation, Membrane Properties, and Thermodynamics

Vocabulary practice flashcards covering enzyme regulation mechanisms, membrane structure, solutions, thermodynamics, and metabolic reaction energetics based on lecture notes.

Irreversible Binding

A form of enzyme binding where an inhibitor attaches permanently, preventing the enzyme from being active.

Reversible Regulation

A type of enzyme regulation where an inhibitor or activator is not bound permanently and can be removed depending on on/off rates or removal by another enzyme.

Competitive Inhibition

An inhibitory process where a molecule binds directly to the active site and competes with the substrate, preventing substrate binding and reaction catalysis.

Allosteric Regulation

The modification of an enzyme caused by a molecule binding to a location other than the active site, which can either activate or inhibit enzyme activity.

Noncompetitive Inhibition

Inhibition occurring when an inhibitor binds to an enzyme somewhere other than the active site, altering the active site's shape so substrate cannot bind; identical to allosteric inhibition.

Allosteric Activator

A regulatory molecule that binds to an enzyme at a site other than the active site, changing the active site's shape to allow substrate binding.

Feedback Inhibition

A cellular control mechanism in which the product of a metabolic pathway acts as an inhibitor of an early enzyme in that pathway to slow down or stop unnecessary production.

Saturation

The condition where increasing substrate concentration no longer increases the rate of an enzyme-catalyzed reaction.

Denaturation

The unfolding of an enzyme's protein structure caused by extreme pH or excessive temperature, destroying the active site and reducing the reaction rate to zero.

Saturated Fats

Fatty acids containing only single carbon-carbon bonds and no double bonds, leading to straight molecules that pack tightly together and are less fluid.

Peripheral Membrane Proteins

Proteins that reside outside the hydrophobic interior bilayer of a membrane and may interact with the hydrophilic phospholipid head groups.

Hypotonic Solution

A solution with a lower solute concentration than the inside of a cell, driving net water movement into the cell and causing it to burst or lyse.

Entropy

A term coined in the 1860s denoting the irreversible dispersion of usable energy into disordered, unusable energy.

Second Law of Thermodynamics

A fundamental law stating that with each chemical reaction, the amount of usable energy decreases while entropy increases.

Hydrolysis

A chemical reaction that breaks down larger molecules into smaller molecules, such as breaking peptide bonds in proteins using water.

Endergonic Reaction

A chemical reaction that overall requires or consumes energy.

Exergonic Reaction

A chemical reaction that overall releases energy, such as the breakdown of larger molecules into smaller ones.