Question

Microtubules are the constituents of

• A. Spindle fibres, Centrioles and Cilia
• B. Centrioles, spindle fibres and chromatin
• C. Centrosome, Nucleosome and Centrioles
• D. Cilia, Flagella and Peroxisomes

Answer 1

The Correct Option is A

To solve the question regarding the constituents of microtubules, we need to understand the biological structures and their functions.

Microtubules are cylindrical structures that play a vital role in maintaining the shape of the cell, enabling intracellular transport, and facilitating cell division. They are one of the major components of the cytoskeleton in cells. Let's look at how they relate to the given options:

1. Spindle fibres, Centrioles, and Cilia:
   • Spindle fibres: During cell division, microtubules form the spindle fibres, which help separate chromosomes into daughter cells.
   • Centrioles: These are cylindrical structures composed of microtubules and play a role in organizing the microtubules in the spindle apparatus during cell division.
   • Cilia: These are hair-like structures that help in cell movement and are composed of microtubules arranged in a specific pattern.
   • Thus, microtubules are indeed constituents of spindle fibres, centrioles, and cilia.
2. Centrioles, spindle fibres, and chromatin:
   • Chromatin: This is a complex of DNA and proteins, not directly related to microtubules.

   Since chromatin is not related to microtubules, this option is incorrect.

3. Centrosome, Nucleosome, and Centrioles:
   • Nucleosome: This is the basic unit of DNA packaging in eukaryotes and does not involve microtubules.

   The inclusion of nucleosomes, which are unrelated to microtubules, makes this option incorrect.

4. Cilia, Flagella, and Peroxisomes:
   • Flagella: Similar to cilia, flagella are also composed of microtubules.
   • Peroxisomes: These are involved in enzymatic processes, not related to microtubules.

   The presence of peroxisomes, which do not involve microtubules, makes this option incorrect.

Therefore, the correct answer is Spindle fibres, Centrioles, and Cilia, as all three structures involve microtubules.