The correct option is (c).
Explanation
The cell wall is a non-living, rigid structure that forms an outer covering for the plasma membrane in certain organisms. It provides shape, protection, and structural support to the cell.- Statement 1 is Correct: The cell wall is a characteristic feature of plant cells, fungi, and bacteria. It is absent in animal cells. In plants, it is primarily composed of cellulose; in fungi, it consists of chitin; and in bacteria, it is made of peptidoglycan.
- Statement 2 is Incorrect: The cell wall is not mainly composed of lipids. In plants, the cell wall is predominantly made of cellulose (a complex carbohydrate). Lipids and proteins are the primary constituents of the plasma membrane (cell membrane), not the cell wall.
- Statement 3 is Correct: The rigid cell wall allows cells to withstand very dilute (hypotonic) external media without bursting. When placed in such media, the cell takes up water by osmosis and swells, building up pressure against the wall (turgor pressure). The wall exerts an equal and opposite pressure against the swollen cell, preventing it from bursting.
Key Takeaway: The cell wall is a rigid outer layer found in plants (cellulose), fungi (chitin), and bacteria (peptidoglycan), distinct from the lipid-based plasma membrane found in all cells.