Vacuole
A membrane-enclosed compartment in a cell that stores or transports substances and can help regulate water balance, digestion, or structural support.
Tonoplast: The membrane surrounding a plant vacuole, controlling exchange between its contents and the cytoplasm. Its transport proteins regulate what enters and leaves the central vacuole.
Endomembrane system: A network of membranes and compartments that modifies, transports, and sorts proteins and lipids in eukaryotic cells. Vacuoles exchange membrane and cargo with other parts of this cellular network.
Central vacuole: The large, usually fluid-filled vacuole occupying much of a mature plant cell. Its storage capacity and pressure help determine plant-cell size and form.
Peroxisome: A membrane-bound organelle that carries out oxidative reactions, including fatty-acid breakdown and peroxide detoxification. Unlike a vacuole, a peroxisome is defined by specialized oxidative metabolism.
V-type ATPase: A membrane protein complex that uses ATP to move protons across cellular membranes. It acidifies many vacuoles, enabling degradation and storage processes.
Eukaryotic cell: A cell whose DNA is enclosed in a nucleus and whose interior contains membrane-bound organelles. Vacuoles are membrane-bound compartments found in eukaryotic cells.
Contractile vacuole: A cellular organelle that collects and expels excess water, especially in many freshwater protists. It shows how vacuoles can actively protect cells from water influx.
Endosome: A membrane-bound compartment that sorts material internalized from the cell surface. Endosomes primarily route incoming cargo, while vacuoles often store or digest it.
Osmosis: The net movement of water across a selectively permeable membrane toward higher solute concentration. Water movement into the vacuole generates turgor pressure in plant cells.
Cell membrane: The selectively permeable lipid bilayer that separates a cell from its environment. Like the cell membrane, a vacuolar membrane controls molecular exchange across a boundary.