Question

Microfilaments are composed mainly of a protein called
A. Actin
B. Tubulin
C. Myosin
D. Chitin

Answer 1

Hint: The protein filaments of cytoplasm as found in Eukaryotic cells are called Microfilaments. They are adapted to interact with various other proteins contained inside the cells. They also perform the cellular movements which include gliding, contradiction and cytokinesis.

Complete Answer:
1. Tubulin protein belongs to the superfamily of Globular proteins. They are related to microtubules inside which a major part of the cytoskeleton can be noticed. This is the feature of eukaryotic cells.
2. Myosin belongs to the superfamily of Motor Proteins. They are specifically known for their major contribution in muscular contraction. Microfilaments are seen as they are connected with Myosin, but they are composed from this type of protein.
3. In the cell walls of fungi, the chitin can be found. They are the primary component in those cell walls. The same protein can be found in the exoskeletons of arthropods, in the radula of mollusks and else. They are not associated with microfilaments.
4. The Actin is the type of multifunctional globular protein. It is found in Eukaryotic cells and their main function is to compose Microfilaments. Thus, it has been clear that behind the composition of microfilaments, the Actin Protein has a major role which we can’t find in other types of proteins that are mentioned in above options.

Hence the correct answer is option A.

Note: The height of microfilaments generally is 7 nanometre and this is composed with two strands of actin. There are several functions of microfilaments. Among them, the salient functions are: cytokinesis, amoeboid movements, cell motility (the ability of movement by its own), changes in cell shapes, endo- and exocytosis, the contractility in cells and providing mechanical stability to cells when required.