Question 2

Flagellum enables cells to move through their environments.

Cells utilize flagella as a cellular appendage to propel themselves through various environments, facilitating movement.

A) Flagellum

Flagella are long, whip-like structures that extend from the cell surface, allowing for motility. They are essential for the movement of many unicellular organisms, such as sperm cells in animals and certain bacteria, enabling them to navigate through liquid environments effectively.

B) Cell membrane

While the cell membrane is crucial for maintaining the integrity and functionality of the cell, it does not serve as a means for movement. The membrane provides a barrier and regulates the entry and exit of substances, but it lacks the necessary structures for locomotion.

C) Transport protein

Transport proteins are involved in the movement of molecules across the cell membrane but are not responsible for cell movement through environments. They facilitate the transport of nutrients and waste products rather than enabling the cell itself to move.

D) Receptor

Receptors are proteins that receive signals from outside the cell, facilitating communication and response to environmental changes. However, they do not play a role in physical movement through environments, making them unrelated to cellular motility.

Conclusion

The flagellum is the definitive cellular appendage that enables movement, distinguishing it from the other options that do not contribute to locomotion. The cell membrane, transport proteins, and receptors serve critical functions, but none provide the capability for the cell to move through its environment. Thus, flagella are essential for motility in many organisms.