Cell Transport Processes Vocabulary

Flashcards defining essential cell transport vocabulary, including passive diffusion, osmosis, active transport mechanisms, membrane solutions, bulk transport, and the sodium-potassium pump.

Diffusion

A passive transport process involving the movement of molecules or gases down their concentration gradient from high to low concentration, which can transport solutes and sometimes uses channel proteins.

Osmosis

The passive transport and diffusion of water molecules across a semipermeable membrane.

Active Transport

The movement of molecules across a cell membrane against their concentration gradient, from low to high concentration, requiring input of extra energy (such as ATP) and carrier proteins.

Facilitated Diffusion

Diffusion of molecules across a cell membrane from high to low concentration taking place directly through a protein channel.

Aquaporin

A specific protein channel in the cell membrane that transports water molecules.

Hypotonic Solution

A solution with a lower solute concentration than the solute concentration inside the cell.

Hypertonic Solution

A solution with a higher solute concentration than the solute concentration inside the cell.

Isotonic Solution

A solution with an equal solute concentration to the solute concentration inside the cell.

Homeostasis

The process of maintaining a balanced internal environment inside a cell.

Phospholipids

The lipid molecules that make up the structure of the cell membrane.

Endocytosis

An active transport process that uses vesicles derived from the plasma membrane to move large materials or macromolecules into the cell by folding inward.

Exocytosis

An active transport process where internal vesicles (such as from the Golgi) fuse with the cell membrane to release or secrete macromolecules out into the extracellular space.

Phagocytosis

A form of endocytosis involving the uptake or engulfment of solids, such as bacteria, into the cell.

Pinocytosis

A form of endocytosis involving the uptake of liquids into the cell.

Receptor-Mediated Endocytosis

A type of endocytosis that is regulated with the use of membrane receptors that signal when specific target molecules, such as lipids, are present.

Plant Mineral Ion Absorption

An example of active transport where plant root cells absorb mineral ions from low-quality soil against their concentration gradient.

Sodium-Potassium Pump

A protein pump in the cell membrane that uses ATP to pump three sodium ions out of the cell and two potassium ions into the cell against their concentration gradients to establish an electrochemical gradient and maintain resting potential.

Phosphorylation

The process where ATP releases one of its phosphate groups and transfers it to a protein pump, causing the protein to change shape.

Resting Potential

The electrical charge difference across the cell membrane at rest, maintained as more negative inside than outside through the sodium-potassium pump and potassium diffusion channels.