Choanocytes

Definition

Choanocytes are specialized flagellated cells found in sponges (phylum Porifera) that play a crucial role in the feeding process. These cells create water currents through the sponge's body by beating their flagella, allowing for the intake of food particles and oxygen while also aiding in the removal of waste products. The structure and function of choanocytes are essential for understanding the basic biology and ecology of sponges.

5 Must Know Facts For Your Next Test

1. Choanocytes are vital for sponges' filter-feeding mechanism, allowing them to extract food particles from water.
2. These cells possess a unique structure with a collar made up of microvilli that traps food particles as water flows past.
3. The movement of flagella on choanocytes generates a constant flow of water, which is essential for maintaining the sponge's internal environment.
4. Choanocytes also play a role in reproduction by transforming into gametes during sexual reproduction in some sponge species.
5. The efficiency of choanocytes in filtering water contributes to the ecological roles sponges play in aquatic ecosystems as they help maintain water quality.

Review Questions

• How do choanocytes contribute to the feeding process in sponges?
  • Choanocytes contribute to feeding in sponges by generating water currents through their flagella, which pulls water into the sponge's body. As water passes through, food particles become trapped in the collar structure of these cells. This allows sponges to efficiently filter feed, capturing nutrients and oxygen while also facilitating waste removal.
• What structural features of choanocytes enable them to fulfill their function effectively?
  • Choanocytes are characterized by their flagella and collar-like structures made of microvilli. The flagella beat to create water currents, while the collar traps food particles as water flows by. This unique combination allows choanocytes to maximize feeding efficiency, ensuring that sponges can thrive in various aquatic environments.
• Evaluate the ecological significance of choanocytes in sponge populations and their environments.
  • Choanocytes play a critical role in sponge populations by enabling efficient filter-feeding, which directly influences water quality and nutrient cycling in their environments. By filtering out organic matter and microorganisms, sponges help maintain clear water conditions that benefit other aquatic organisms. Furthermore, the presence of healthy sponge populations, supported by active choanocytes, indicates a balanced ecosystem where diverse marine life can thrive.

Related terms

spongocoel: The central cavity of a sponge where water flows through, facilitating the movement of nutrients and waste.

osculum: The large opening at the top of a sponge through which water exits after being filtered by choanocytes.

collar cell: Another name for choanocytes, highlighting their distinctive collar-like structure surrounding the flagellum that helps capture food particles.