Membrane Structure and Function

Flashcards summarizing key concepts from the lecture on membrane structure and function.

Plasma Membrane

The boundary that separates the living cell from its surroundings.

Selective Permeability

Property of plasma membranes that allows some substances to cross more easily than others.

Phospholipids

The most abundant lipids in the plasma membrane, which are amphipathic molecules.

Amphipathic

Molecules that contain both hydrophobic and hydrophilic regions.

Fluid Mosaic Model

Describes the membrane as a fluid structure with a mosaic of various proteins embedded.

Integral Proteins

Proteins that penetrate the hydrophobic core of the membrane.

Transmembrane Proteins

Integral proteins that span the membrane.

Channel Proteins

Transport proteins that allow certain molecules or ions to cross the membrane through a hydrophilic channel.

Aquaporins

Channel proteins that facilitate the passage of water across the membrane.

Diffusion

The tendency for molecules to spread out evenly into the available space.

Osmosis

The diffusion of water across a selectively permeable membrane.

Isotonic Solution

A solution where solute concentration is the same as inside the cell, resulting in no net water movement.

Hypertonic Solution

A solution with a greater solute concentration than inside the cell, causing the cell to lose water.

Hypotonic Solution

A solution with a lower solute concentration than inside the cell, causing the cell to gain water.

Active Transport

The movement of substances against their concentration gradient, requiring energy.

Cotransport

A mechanism that occurs when active transport of a solute indirectly drives transport of other substances.

Exocytosis

The process through which large molecules are transported out of the cell via vesicles.

Endocytosis

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

Phagocytosis

A type of endocytosis known as 'cellular eating' that involves ingesting large particles.

Pinocytosis

A type of endocytosis known as 'cellular drinking' that involves ingesting extracellular fluid.

Receptor-Mediated Endocytosis

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