Cell Membrane & Transport - Biol 120

A comprehensive set of flashcards covering essential vocabulary and concepts related to cell membrane structure and transport mechanisms.

Cell Membrane

The boundary that separates the living cell from its non-living surroundings, exhibiting selective permeability.

Phospholipid Bilayer

A double layer of phospholipids that forms the basis of the cell membrane.

Fluid Mosaic Model

A model that describes the structure of the plasma membrane as a fluid combination of phospholipids and proteins.

Selective Permeability

The ability of the cell membrane to allow some substances to cross more easily than others.

Active Transport

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

Passive Transport

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

Osmosis

The diffusion of water across a selectively permeable membrane.

Hypertonic Solution

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

Hypotonic Solution

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

Isotonic Solution

A solution with an equal solute concentration to that inside the cell, resulting in no net water movement.

Endocytosis

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

Exocytosis

The process by which materials are expelled from the cell via vesicle fusion with the plasma membrane.

Facilitated Diffusion

The passive transport of molecules across a plasma membrane via a transport protein.

Aquaporins

Channel proteins that facilitate the transport of water across the cell membrane.

Contractile Vacuole

An organelle in some protists that helps maintain osmotic balance by expelling excess water.

Sodium-Potassium Pump

An active transport system in animal cells that pumps sodium out and potassium into the cell.

Transport Proteins

Proteins that assist in the movement of ions and molecules across cell membranes.

Turgor Pressure

The pressure exerted by fluid in the vacuole of a plant cell that maintains its shape.

Phagocytosis

A type of endocytosis where the cell engulfs large particles or cells.

Pinocytosis

A type of endocytosis where the cell ingests small particles or liquids.

Receptor-Mediated Endocytosis

Endocytosis triggered by the binding of ligands to specific receptors on the cell membrane.

Desaturase

An enzyme that catalyzes the formation of double bonds in fatty acid tails to promote membrane fluidity.

Lipid Bilayer

The arrangement of phospholipids in the cell membrane, with hydrophobic tails facing inward and hydrophilic heads facing outward.