Which type of movement is made possible by the arrangement of actin fibers?
A Cellular crawling
B Flagellar movement
C Cilia movement
The correct answer and explanation is:
The correct answer is A. Cellular crawling.
Actin fibers are integral to the process of cellular movement, specifically in cellular crawling. This type of movement is essential for various physiological processes such as wound healing, immune responses, and tissue development. Actin filaments, which are part of the cytoskeleton, form a dynamic network inside the cell. This network undergoes polymerization and depolymerization, allowing the cell to extend its membrane in the direction of movement. These extensions, called lamellipodia or filopodia, help the cell crawl along surfaces.
Cellular crawling involves the interaction between actin filaments and other proteins, such as myosin. When actin filaments polymerize at the leading edge of the cell, they push the membrane forward. At the same time, actin at the rear of the cell depolymerizes, allowing the cell to move forward. Myosin, a motor protein, assists in pulling the rear of the cell toward the front by interacting with the actin filaments, contributing to the movement.
Flagellar movement (B) and ciliary movement (C) are different types of cellular movement, but they are not directly related to actin fibers. Flagella and cilia are composed of microtubules arranged in a “9+2” structure, and their movement is driven by motor proteins like dynein and kinesin. These structures are involved in locomotion in single-celled organisms and the movement of fluids across surfaces in multicellular organisms, but they do not rely on actin filaments for their function. Therefore, the correct answer is A. Cellular crawling.