Which statement best describes an actin filament?

• A. Actin filaments are rigid structures that form the spindle apparatus during cell division.
• B. Actin filaments are hollow tubes that provide structural support to the cell.
• C. Actin filaments are thin, flexible fibers that play a key role in muscle contraction and cell movement.
• D. Actin filaments are composed of tubulin and are involved in intracellular transport.

Answer: (C)

Verified step by step guidance

1. Understand the role of actin filaments in the cell: Actin filaments are part of the cytoskeleton, which provides structural support and plays a role in cell movement and muscle contraction.
2. Differentiate actin filaments from other cytoskeletal elements: Unlike microtubules, which are hollow tubes made of tubulin, actin filaments are thin and flexible fibers composed of actin protein.
3. Recognize the function of actin filaments in muscle contraction: Actin filaments interact with myosin to facilitate muscle contraction, a key function that distinguishes them from other cytoskeletal components.
4. Identify the role of actin filaments in cell movement: Actin filaments are involved in processes like cell crawling and changes in cell shape, contributing to their flexibility and dynamic nature.
5. Conclude that the correct description of actin filaments is that they are thin, flexible fibers that play a key role in muscle contraction and cell movement, distinguishing them from rigid structures or hollow tubes.