Membrane Transport and Cellular Processes

Vocabulary flashcards covering cellular membrane transport mechanisms, tonicity concepts, and energy requirements from Chapter 1 to Chapter 7.

Selectively permeable

A characteristic of cellular membranes that allows some substances to cross while restricting others, maintaining disparities in solute concentrations inside and outside the cell.

Concentration gradient

A difference in solute concentration between two regions where a solute is more concentrated in one area than in another.

Diffusion

The process by which molecules spread out evenly from an area of higher concentration to an area of lower concentration driven by physics.

Passive transport

The movement of small molecules across cell membranes down their concentration gradient without requiring any expenditure of energy.

Simple diffusion

A form of passive transport where solutes move directly down their concentration gradient from high to low concentration across a membrane without using energy or transport proteins.

Osmosis

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

Isotonic environment

An environment in which the solute concentration outside the cell is equal to the solute concentration inside the cell, resulting in no net movement of water.

Hypotonic environment

An environment where the solute concentration outside the cell is less than inside the cell, causing water to rush into the cell.

Turgor pressure

The hydrostatic force exerted by water inside interior plant cells against their cell walls when in a hypotonic environment, keeping the plant upright.

Hypertonic environment

An environment where the solute concentration outside the cell is greater than inside the cell, causing water to exit the cell.

Plasmolysis

The process in plant cells placed in a hypertonic environment where the plasma membrane pulls away from the cell wall as water leaves the cell.

Facilitated diffusion

A type of passive transport that moves molecules across a membrane down their concentration gradient using transport proteins without expending energy.

Active transport

The transport of molecules across cell membranes requiring energy (typically ATP) and transport proteins, moving substances against their concentration gradient from low to high concentration.

Adenosine triphosphate (ATP)

An energy-carrying molecule found in all cells composed of an adenine base, a sugar, and three phosphate groups.