key term - Pseudopodia

Definition

Pseudopodia are temporary, foot-like extensions of a cell's cytoplasm that enable movement and the capture of food. These structures play a crucial role in the locomotion of certain cells, particularly in amoebas and some white blood cells, allowing them to navigate their environments and engage in processes like phagocytosis.

5 Must Know Facts For Your Next Test

1. Pseudopodia can vary in shape and size, allowing cells to adapt to their surroundings while facilitating movement and feeding.
2. The extension and retraction of pseudopodia are driven by the cytoskeleton, specifically actin filaments, which provide the necessary support and force.
3. In addition to locomotion, pseudopodia help cells interact with their environment, such as capturing prey or sensing chemical signals.
4. Certain immune cells, like macrophages, use pseudopodia for phagocytosis to engulf pathogens and debris, playing a key role in the body's defense mechanisms.
5. Pseudopodia are not permanent structures; they form and disintegrate dynamically as cells move and respond to environmental stimuli.

Review Questions

• How do pseudopodia facilitate movement in amoeboid organisms?
  • Pseudopodia allow amoeboid organisms to move by extending outward from the main body of the cell. This extension is powered by the cytoskeleton, primarily through the polymerization of actin filaments. By forming these temporary projections, amoebas can anchor one end of their body and pull themselves forward, enabling them to crawl through their environment.
• Discuss the role of pseudopodia in phagocytosis and how this process contributes to immune response.
  • In phagocytosis, pseudopodia extend around pathogens or debris, effectively engulfing them. Once surrounded, the material is internalized into a vacuole where it can be broken down by enzymes. This process is crucial for immune cells like macrophages, as it allows them to eliminate harmful microorganisms and clean up cellular waste, thereby maintaining health.
• Evaluate how disruptions in cytoskeletal function could impact pseudopodia formation and cellular movement.
  • Disruptions in cytoskeletal function can severely affect pseudopodia formation and cellular movement. If actin filaments are compromised, the cell may struggle to extend or retract its pseudopodia effectively. This can lead to impaired locomotion, making it difficult for cells to migrate towards infection sites or food sources. Consequently, this could weaken the immune response and hinder basic survival processes for organisms relying on amoeboid movement.

Related terms

Amoeboid movement: A type of movement characterized by the formation of pseudopodia, commonly seen in amoebas, which allows them to crawl through their environment.

Phagocytosis:

The process by which a cell engulfs solid particles, such as bacteria or cellular debris, using pseudopodia to surround and internalize the material.

Cytoskeleton:

A network of protein filaments and tubules within a cell that provides structure, shape, and support for cell movement, including the formation of pseudopodia.