Pseudopodia

Pseudopodia, also known as pseudopods, are temporary cytoplasmic projections or "false feet" used for locomotion and engulfing food in some unicellular organisms, such as amoebas and some white blood cells. The term "pseudopodia" comes from the Greek words "pseudes" meaning false, and "pous" meaning foot.

Structure of Pseudopodia

Pseudopodia are formed by the extension of the cytoplasm, supported by microfilaments of actin. The extension is driven by the assembly of actin filaments at the leading edge of the pseudopod, and the subsequent disassembly of filaments at the rear, allowing the cell to move forward.

Functions of Pseudopodia

Pseudopodia serve several functions, including:

• Locomotion: Unicellular organisms, such as amoebas, use pseudopodia to move and change their shape as they navigate their environment.
• Feeding: Amoebas and other protozoa use pseudopodia to engulf food particles by surrounding and engulfing them in a process called phagocytosis.

Study Guide

Key Concepts

• Definition of pseudopodia
• Structure of pseudopodia
• Functions of pseudopodia

Study Tips

• Review the process of phagocytosis and how pseudopodia are involved in engulfing food particles.
• Understand the role of actin filaments in the formation and extension of pseudopodia.
• Compare and contrast the locomotion mechanisms of organisms that use pseudopodia versus those that use flagella or cilia.

Practice Questions

1. What are pseudopodia and what are their functions?
2. Describe the structure of pseudopodia and the role of actin filaments in their formation.
3. Explain how pseudopodia are involved in the process of phagocytosis.