Cell Transport and Membrane Structure Vocabulary

Vocabulary flashcards covering cell membrane components, passive and active transport mechanisms, and osmotic solution types based on lecture notes.

Cell Membrane (Plasma Membrane)

A boundary created between the cell and the outside environment that helps maintain homeostasis and is made up of a phospholipid bilayer.

Phospholipid Bilayer

The core structure of the cell membrane consisting of hydrophilic phosphate heads and hydrophobic fatty acid tails.

Selectively Permeable

A property of the cell membrane meaning it lets some substances through, but not others.

Homeostasis

The process of maintaining a stable, balanced internal environment to survive and function best, even when external conditions change.

Carbohydrate Chains

Structures in the cell membrane that help cells recognize each other and interact.

Concentration Gradient

The path along which substances move from areas of high concentration to areas of low concentration.

Passive Transport

The movement of substances across the membrane down the concentration gradient (from high to low concentration) without the use of energy.

Simple Diffusion

A type of passive transport where particles move directly through the bilayer from an area of higher concentration to a lower concentration until equilibrium is reached.

Facilitated Diffusion

Movement of particles down the concentration gradient (high to low) across the membrane with the help of a transport protein, such as a channel or carrier protein.

Aquaporins

Protein channels embedded in the membrane through which water moves during osmosis.

Active Transport

The movement of substances across the membrane against or up the concentration gradient (from low to high concentration), requiring energy in the form of ATP.

Protein Pumps

Membrane proteins used in active transport that require ATP to move large molecules or ions across the membrane against the concentration gradient.

Endocytosis

A type of active transport using vesicles where substances enter the cell, such as an amoeba engulfing a large particle of food.

Exocytosis

A type of active transport using vesicles where substances exit the cell.

Osmosis

The movement or diffusion of water into and out of a cell across a semipermeable membrane from an area of high water concentration to an area of low water concentration.

Solutes

Dissolved substances within a solution.

Hypertonic Solution

A solution with a high concentration of solutes ('hyper' = over / above) and low water concentration, which causes water to leave the cell via osmosis, causing the cell to shrivel and shrink.

Isotonic Solution

A solution with equal solute concentrations inside and outside the cell ('iso' = equal), where no net movement of water occurs and the cell is at equilibrium.

Hypotonic Solution

A solution with a low concentration of solutes ('hypo' = low / below), which causes water to move into the cell via osmosis so the cell swells and can burst.

Large Central Vacuole

The structure within a plant cell where water driven from the soil into plant roots via osmosis is stored.