Plant Vacuoles:
- Plant cells have a large central vacuole that can occupy up to 90% of the cell's volume.
- It is surrounded by a single membrane called the tonoplast.
- Functions of plant vacuoles include:
1. Storage: Vacuoles store various substances such as water, salts, sugars, proteins, and pigments.
2. Cellular expansion: As the vacuole fills with water, it exerts pressure on the cell wall, causing the cell to expand and grow.
3. Protection: Vacuoles can store toxic substances away from the sensitive cellular components, thus protecting the cell.
4. Maintains cell shape: The central vacuole helps maintain the shape of the plant cell.
5. Digestion: Some vacuoles contain hydrolytic enzymes that help digest food particles and other materials.
6. Waste storage: Vacuoles also store waste products and toxins that the plant needs to isolate from the rest of the cell.
Animal Vacuoles:
- Animal cells typically have multiple smaller vacuoles instead of a single large one.
- They are enclosed by a membrane and vary in size and function depending on the cell type.
- Functions of animal vacuoles:
1. Food vacuoles (also known as digestive vacuoles): These vacuoles are formed when the cell engulfs food particles through phagocytosis. They contain digestive enzymes that break down the food into smaller molecules.
2. Contractile vacuoles: These vacuoles are found in some freshwater protozoans and other aquatic animals. They collect excess water from the cell and pump it out to maintain proper water balance.
3. Lysosomes: Lysosomes are membrane-bound organelles that contain hydrolytic enzymes. They break down complex molecules, recycle worn-out cell components, and play a role in cell death.
4. Secretory vacuoles: Secretory vacuoles store and release specific substances such as hormones, digestive enzymes, or waste products.
5. Gas vacuoles: Gas vacuoles are found in certain microorganisms, providing buoyancy and aiding in floating or movement in aquatic environments.