[Campbell Biology P.917] Regarding the cellular-level defense mechanism involving raphides i... | Practice Question

Regarding the cellular-level defense mechanism involving raphides in plants like taro Colocasia esculenta , which statement is correct?

  • A: Raphides are calcium oxalate crystals that mechanically tear flesh during removal.
  • B: Raphides are needle-shaped crystals primarily composed of silicon dioxide.
  • C: Raphides penetrate soft tissues and act as carriers for an irritant, which can be destroyed by cooking.
  • D: Idioblasts are specialized cells that store alkaloids like morphine and heroin.

Explanation

The text states that idioblasts contain needle-shaped crystals of calcium oxalate called raphides. They penetrate soft tissues of the tongue and palate, making it easier for an irritant possibly a protease to enter, causing temporary swelling. The raphides act as a carrier for the irritant, and importantly, the irritant is destroyed by cooking.