How is a sting cell in Hydra adapted for its function?
The correct answer and explanation is:
Answer:
A sting cell in Hydra, also known as a nematocyst or cnidocyte, is adapted for its function by having a specialized capsule containing a coiled, barbed, and often venomous thread that can rapidly evert to sting and capture prey or defend the organism.
Explanation (300 words):
Sting cells, or nematocysts, are unique specialized cells found in Hydra and other cnidarians. Their primary function is to capture prey and provide defense against predators. These cells are highly adapted both structurally and functionally to fulfill this role effectively.
Structurally, a sting cell contains a capsule called a nematocyst. Inside this capsule, there is a tightly coiled, hollow thread that is barbed or has spines. The capsule is under high osmotic pressure, which allows the thread to eject explosively when triggered. The trigger is usually a mechanical or chemical stimulus detected by a hair-like structure called a cnidocil on the surface of the sting cell.
When the cnidocil is stimulated—by the touch of prey or a threat—the capsule’s lid opens, and the internal thread rapidly everts, sometimes in less than a millisecond. The thread pierces the target and injects venom that can immobilize or kill small prey, such as tiny aquatic animals, making them easier for the Hydra to ingest.
This rapid and powerful mechanism allows Hydra to be an effective predator despite its simple body plan. The venomous sting can also deter predators, providing protection. Additionally, the sting cells are strategically located on the tentacles of the Hydra, where prey are most likely to come into contact with them.
In summary, the sting cell’s adaptations—a pressurized capsule, a barbed venomous thread, a sensitive trigger mechanism, and strategic placement—enable Hydra to catch prey efficiently and defend itself, demonstrating a remarkable evolutionary specialization for its survival needs.