Cell Membrane Structure and Function

These flashcards cover key vocabulary terms related to the structure and function of cellular membranes, essential for understanding transport mechanisms, membrane properties, and the interactions between cells and their environments.

Fluid Mosaic Model

Describes the structure of the plasma membrane as a mosaic of various proteins that float in or on the fluid lipid bilayer.

Selective Permeability

The property of cell membranes that allows certain substances to pass through while blocking others.

Passive Transport

The movement of substances across a cell membrane without the use of energy; includes diffusion and osmosis.

Active Transport

The movement of substances across a cell membrane against their concentration gradient, requiring energy input, often in the form of ATP.

Exocytosis

A process by which a cell expels materials in vesicles that fuse with the plasma membrane to release their contents outside the cell.

Endocytosis

The process by which a cell takes in materials by forming vesicles from the plasma membrane.

Aquaporin

A membrane protein that facilitates the rapid transport of water through the cell membrane.

Membrane Fluidity

The viscosity of the lipid bilayer of a cell membrane that affects the movement of proteins and lipids within it.

Integral Proteins

Proteins that penetrate the hydrophobic interior of the lipid bilayer; primarily function in transport.

Peripheral Proteins

Proteins that are loosely bound to the surface of the membrane or to integral proteins.

Glycoproteins

Proteins with carbohydrate chains attached that play key roles in cell-cell recognition.

Cotransport

A mechanism that couples the transport of one solute down its concentration gradient to the transport of another solute against its gradient.

Ion Channels

Membrane proteins that provide corridors for specific ions to cross the membrane.

Membrane Potential

The voltage across a cell's plasma membrane due to the unequal distribution of ions; important for nerve and muscle function.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water, important for cell volume regulation.