Membrane Structure and Function

Flashcards covering key terms and concepts related to membrane structure and function.

Amphipathic

Molecules that contain both hydrophobic and hydrophilic regions, such as phospholipids.

Fluid Mosaic Model

Describes the plasma membrane structure as a mosaic of various proteins embedded in a fluid lipid bilayer.

Selectively Permeable

A property of biological membranes that allows some substances to pass through while restricting others.

Passive Transport

The movement of substances across a membrane without the expenditure of energy.

Osmosis

The diffusion of free water across a selectively permeable membrane.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water.

Hypertonic Solution

A solution with a higher solute concentration compared to the inside of the cell, causing water to leave the cell.

Hypotonic Solution

A solution with a lower solute concentration compared to the inside of the cell, causing water to enter the cell.

Active Transport

The movement of solutes against their concentration gradients, requiring energy.

Exocytosis

A process where transport vesicles fuse with the plasma membrane to release contents outside the cell.

Endocytosis

The process by which cells internalize substances by engulfing them in vesicles.

Phagocytosis

A form of endocytosis in which a cell engulfs particles by extending pseudopodia around them.

Pinocytosis

A form of endocytosis where the cell takes in extracellular fluid and dissolved solutes.

Receptor-mediated Endocytosis

A form of endocytosis in which cells internalize molecules bound to specific receptors.

Transport Proteins

Proteins that facilitate the diffusion of substances across a membrane.

Channel Proteins

Transport proteins that provide corridors for specific molecules or ions to cross the membrane.

Carrier Proteins

Transport proteins that bind to molecules and change shape to shuttle them across the membrane.

Aquaporins

Channel proteins that facilitate the rapid transport of water molecules across the membrane.