Chapter_5_Lipus

Fluid Mosaic Model

Describes the structure of a membrane as a mosaic of diverse protein molecules embedded in a fluid phospholipid bilayer.

Passive Transport

Diffusion across a membrane without the need for energy investment.

Active Transport

The movement of molecules against their concentration gradient, requiring energy, typically in the form of ATP.

Osmosis

The diffusion of water across a selectively permeable membrane.

Endocytosis

The process by which a cell takes in large molecules by engulfing them with its membrane.

Exocytosis

The process by which a cell exports bulky materials such as proteins and polysaccharides.

Tonicity

A term describing the ability of a surrounding solution to cause a cell to gain or lose water.

Hydrolysis of ATP

The process of ATP breaking down into ADP and a phosphate group, releasing energy.

Enzyme

A protein that acts as a catalyst to speed up chemical reactions by lowering the activation energy.

Competitive Inhibitor

A substance that competes with the substrate for the active site of an enzyme.

Noncompetitive Inhibitor

An inhibitor that binds to an enzyme at a site other than the active site and changes its shape.

Gibbs Free Energy

The energy available in a system to do work, indicating the spontaneity of a reaction.

Exergonic Reaction

A chemical reaction that releases energy.

Endergonic Reaction

A chemical reaction that requires energy input and produces products rich in potential energy.

Transport Proteins

Proteins that assist in moving substances across a cell membrane.

Metabolism

The sum of all chemical reactions occurring within a cell.

Aquaporin

A protein channel that facilitates the rapid diffusion of water across cell membranes.

Feedback Inhibition

A regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme involved in its production.