Membrane Structure and Function

These flashcards cover key concepts related to membrane structure and function, making them useful for studying biology.

Plasma Membrane

A selectively permeable boundary that separates the interior of a cell from its external environment.

Fluid Mosaic Model

Describes the plasma membrane as a fluid structure with a diverse mix of proteins embedded within it.

Phospholipids

The most abundant lipids in the plasma membrane, which have hydrophilic heads and hydrophobic tails.

Passive Transport

The movement of substances across a cell membrane without the use of energy.

Osmosis

The diffusion of water through a selectively permeable membrane.

Tonicity

The ability of a surrounding solution to affect the water balance of a cell.

Isotonic Solution

A solution with the same solute concentration as inside the cell, causing no net movement of water.

Hypertonic Solution

A solution with a higher solute concentration than inside the cell, resulting in water loss from the cell.

Hypotonic Solution

A solution with a lower solute concentration than inside the cell, leading to water influx into the cell.

Facilitated Diffusion

A passive transport process that uses membrane proteins to help move substances across the membrane.

Channel Proteins

Proteins that provide corridors that allow specific molecules or ions to cross the membrane.

Carrier Proteins

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

Active Transport

The energy-dependent process of moving molecules against their concentration gradient.

Sodium-Potassium Pump

An active transport mechanism that moves sodium ions out of and potassium ions into the cell.

Endocytosis

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

Phagocytosis

A type of endocytosis in which the cell engulfs 'food' or particles.

Pinocytosis

A type of endocytosis known as 'cellular drinking' where the cell takes in extracellular fluid.

Receptor-Mediated Endocytosis

A process in which cells internalize substances by the binding of ligands to receptors.