Cell Walls & Vacuole
Biology: IB Diploma Higher Level, topic 2.3.2
Cell Wall and Cell Vacuole
The cell wall is a structure external to the plasma membrane. Cell vacuoles are found in plant cell cytoplasm.
Structure of cell walls
Structure of cell walls
- The cell wall is a rigid covering that protects the cell.
- Plant, fungal and algal cells all have cell walls.
- The major organic molecule in fungal cell walls is chitin.
- Plant and algal cell walls are made of cellulose.
- Cellulose is a polysaccharide made up of glucose units.
Function of cell walls
- The cell wall provides structural support and gives shape to the cell.
Structure of cell vacuoles
Structure of cell vacuoles
- Plant cells each have a large central vacuole that occupies most of the area of the cell.
- These vacuoles are surrounded by a membrane called the tonoplast and contain a weak solution of salts and sugars called cell sap.
- Cell vacuoles are found in the cytoplasm of plant cells but are NOT present in animal cells.
Function of cell vacuoles
- The central vacuole allows the cell to remain rigid.
- When the central vacuole holds more water, the vacuole pushes against the cell wall and pressure is maintained. This stops the plant from wilting.
- The vacuole also isolates certain chemicals that are unwanted by the rest of the cell.
Test yourself on Cell Walls & Vacuole
Where is the cell wall located?
The Consequences of Water Loss From Vacuoles