The siliceous cell walls of diatoms are called what?

• A. Holdfast
• B. Mangrove
• C. Frustule
• D. Gas Bladder

Answer: (C)

Diatoms have silica-based cell walls that form a two-piece shell known as the frustule. This frustule is made of hydrated silica and fits together like a tiny, ornate box, with pores and patterns that vary by species. The term frustule is specific to diatoms and is a hallmark of their biology, linking their microscopic form to their well-known fossil material (diatomaceous earth). The other terms refer to structures in different organisms—a holdfast helps algae attach to surfaces, a mangrove is a woody coastal plant, and a gas bladder is a buoyancy structure in some aquatic organisms.