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Porifera and Cnideria quiz #3

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  • How do cnidarians capture and digest their prey, and what specialized cells are involved in this process?
    Cnidarians capture prey using tentacles equipped with cnidocytes, which contain nematocysts—stinging organelles that inject toxins to immobilize prey. They digest food in a gastrovascular cavity, where nutrients are absorbed.
  • What is the main feeding strategy of Porifera and what specialized cells do they use for this process?
    Porifera are filter feeders that use choanocytes, flagellated cells lining the spongocoel, to capture food particles from water by phagocytosis.
  • Describe the function of the spongocoel and osculum in sponges.
    The spongocoel is the central cavity where water flows through the sponge, and the osculum is the opening through which water exits after passing through the body.
  • What role do amoebocytes play in the structure and function of sponges?
    Amoebocytes create structural fibers that support the sponge's body and are responsible for transporting nutrients within the sponge.
  • How do sponges digest their food, and how does this differ from most animals?
    Sponges digest their food intracellularly within the cytoplasm of choanocytes, unlike most animals that digest food extracellularly in an alimentary canal.
  • What are the two main body forms of cnidarians and how do they differ?
    Cnidarians exist as polyps, which are cylindrical and often attached to surfaces, and medusae, which are free-swimming and have tentacles and the mouth on the underside.
  • What specialized cells do cnidarians use to capture prey, and what is the function of nematocysts?
    Cnidarians use cnidocytes, which contain nematocysts—stinging organelles that fire barbs to immobilize prey.
  • Explain the function of the gastrovascular cavity in cnidarians.
    The gastrovascular cavity serves as a central space for digestion and nutrient absorption, as well as distribution of nutrients throughout the body.
  • What type of skeleton do most cnidarians possess and how does it support their body?
    Most cnidarians have a hydrostatic skeleton, where the pressure of fluid within the body cavity provides structural support.
  • What distinguishes anthozoan cnidarians like corals from other cnidarians?
    Anthozoan cnidarians, such as corals, often have exoskeletons made of calcium carbonate, which provide a hard structure unlike the soft bodies of other cnidarians.