Question

Mitotic spindle is mainly composed of which protein :-

• A. Actin
• B. Tubulin
• C. Actomyosin
• D. Myoglobin

Answer 1

The Correct Option is B

 The mitotic spindle is a crucial structure involved in cell division, specifically during mitosis. It is primarily responsible for the separation of chromosomes into the two daughter cells. The main component of the mitotic spindle is the protein tubulin.

1. Understanding the Mitotic Spindle:
   • The mitotic spindle is composed of microtubules, which are dynamic structures that can grow and shrink by the addition or removal of tubulin proteins.
2. Role of Tubulin:
   • Tubulin is a globular protein that polymerizes to form microtubules. It consists of alpha and beta subunits, which align alternately to form the microtubule structure.
   • During mitosis, these microtubules attach to chromosomes at the centromere via structures called kinetochores, facilitating chromosome movement.
3. Eliminating Other Options:
   • Actin: Actin is involved in cell movement and structure but primarily forms microfilaments, not involved in the spindle formation.
   • Actomyosin: Actomyosin refers to a complex of actin and myosin involved in muscle contraction, not spindle formation.
   • Myoglobin: Myoglobin is an oxygen-binding protein in muscle cells and not involved in spindle formation.
4. Conclusion:
   • Based on the composition and function of microtubules, the correct answer is Tubulin.