Overview
This lecture explains the function of vacuoles in cells, comparing their roles in animal, plant, and protist cells.
Vacuole Function and Location
- Vacuoles store water, waste, enzymes, and other materials in eukaryotic cells.
- Eukaryotic cells have membrane-bound organelles and a nucleus.
- Vacuoles are present in plant, animal, and some protist cells, but not in bacterial cells.
Differences Between Plant and Animal Cell Vacuoles
- Plant cell vacuoles are very large, occupying 40–80% of the cell's volume.
- Animal cells have much smaller vacuoles and typically more than one per cell.
- The large plant vacuole helps support the plant cell's structure.
Specialized Vacuoles
- Some single-celled protists have contractile vacuoles that open and close to regulate water levels.
Vacuole Functions Beyond Storage
- Vacuoles help regulate turgor pressure, which is the force pushing the plasma membrane against the cell wall in plants.
- They also store old, damaged organelles for later breakdown.
Key Terms & Definitions
- Vacuole — a membrane-bound sac in a cell used for storage of water, waste, and other materials.
- Eukaryotic cell — a cell with membrane-bound organelles and a nucleus.
- Turgor pressure — pressure from water inside the vacuole that pushes the plasma membrane against the cell wall.
- Contractile vacuole — a special vacuole in some protists that controls water balance.
Action Items / Next Steps
- Review the playlist on cell organelles for further learning.