Membrane Structure and Function

These flashcards cover key terms and concepts related to the structure and function of cell membranes as discussed in the lecture.

Plasma Membrane

The boundary separating the internal environment of a cell from its external environment, regulating the entrance and exit of molecules.

Homeostasis

The maintenance of a steady internal environment within a cell.

Phospholipid Bilayer

A double layer of phospholipids forming the basic structure of the plasma membrane, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Fluid-Mosaic Model

The concept describing the plasma membrane as a mosaic of various proteins embedded in or on the fluid phospholipid bilayer.

Glycolipids

Lipids with attached carbohydrate chains, contributing to cell recognition and signaling.

Glycoproteins

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

Channel Proteins

Proteins that facilitate the passage of specific solutes through the membrane, sometimes with gates that open in response to signals.

Carrier Proteins

Proteins that bind to specific molecules and help them cross the plasma membrane.

Osmosis

The diffusion of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

Isotonic Solution

A solution where the solute concentration is equal both inside and outside the cell, resulting in no net movement of water.

Hypotonic Solution

A solution with a lower solute concentration than inside the cell, causing water to enter the cell and potentially lead to lysis.

Hypertonic Solution

A solution with a higher solute concentration than inside the cell, causing water to exit the cell and potentially lead to crenation.

Active Transport

The movement of molecules across the membrane against their concentration gradient, requiring energy.

Exocytosis

The process by which a cell expels materials by vesicle fusion with the plasma membrane.

Endocytosis

The process by which cells take in substances through vesicle formation, which includes phagocytosis and pinocytosis.

Extracellular Matrix (ECM)

A network of proteins and polysaccharides outside the cell that provides structural and biochemical support.

Adhesion Junctions

Cell junctions that connect cytoskeletal filaments between adjacent cells, providing structural integrity.

Tight Junctions

Cell junctions that seal adjacent cells together, preventing leakage of substances between them.

Gap Junctions

Channels that allow direct communication between adjacent cells, permitting the passage of ions and small molecules.