Cell Membrane Transport: Active and Bulk Transport

Vocabulary flashcards covering active transport mechanisms, protein pumps (such as the sodium-potassium pump), and bulk transport processes including endocytosis, phagocytosis, pinocytosis, and exocytosis.

ADP

Adenosine diphosphate; a molecule naturally present in the cell that is converted into ATP through an electrochemical gradient.

ATP Synthase

An enzyme involved in the process of chemiosmosis that assists in creating ATP.

Chemiosmosis

A process utilizing membrane proteins and an electrochemical gradient to create ATP for the cell to use in other forms of active transport.

Active Transport

The movement of molecules across a cell membrane against their concentration gradient (from low concentration to high concentration), requiring energy in the form of ATP.

Protein Pumps

Specialized carrier proteins that change shape to bind, catch, and release specific molecules across the cell membrane against a concentration gradient using ATP.

Sodium-Potassium Pump

A specialized membrane protein pump that performs active transport by moving $3$ sodium ions out of the cell in exchange for bringing $2$ potassium ions into the cell, both against their concentration gradients.

Bulk Transport

An overarching type of active transport requiring energy to move large quantities or very large molecules into or out of the cell.

Endocytosis

A type of bulk transport where the cell membrane encloses and engulfs incoming molecules to bring them into the cell inside a vesicle.

Vesicle

A small membrane sac composed of a phospholipid bilayer that pinches off from the cell membrane to enclose and transport molecules.

Phagocytosis

A form of endocytosis known as "cellular eating," in which the cell engulfs large, solid particles such as proteins or food into a vesicle.

Pinocytosis

A form of endocytosis known as "cellular drinking," in which the cell engulfs and brings in large amounts of liquids inside a vesicle.

Exocytosis

A form of bulk active transport where a vesicle carrying molecules fuses with the cell membrane to release its contents into the extracellular space outside the cell.

Golgi

The organelle described as the "UPS packaging center of the cell," which packages molecules into vesicles that fuse with the membrane to be exported via exocytosis.