Final answer:
The silicalemma is the outer cell wall made of crystallized silica in diatom algae, while the plasmalemma is the plasma membrane surrounding the cytoplasm. They differ in composition, function, and presence in other cells.
Step-by-step explanation:
In diatom algae, the silicalemma is the outer cell wall made of crystallized silica. It is commonly known as the frustule. This unique cell wall provides protection and support to the diatom cell. On the other hand, the plasmalemma is the plasma membrane that surrounds the cytoplasm of the diatom cell. It controls the movement of substances in and out of the cell.
The silicalemma and plasmalemma differ in composition and function. The silicalemma is rigid and provides structural integrity to diatoms, while the plasmalemma is flexible and allows for cellular processes such as nutrient uptake and waste removal. Additionally, the silicalemma is specific to diatoms, while the plasmalemma is present in all types of cells.