Which is the major microtubule-organising centre (MTOC) in eukaryotic cells involved in various cellular processes, including sensory reception, locomotion, and embryogenesis ?

Centrosome

The correct answer is Option (2) - Centrosome

The major microtubule-organizing center (MTOC) in eukaryotic cells that is involved in various cellular processes, including sensory reception, locomotion, and embryogenesis, is the centrosome.

The centrosome is a specialized organelle found near the nucleus of most animal cells. It consists of a pair of centrioles surrounded by a matrix of proteins. The centrosome serves as the primary site for the organization and nucleation of microtubules, which are dynamic polymers made of tubulin protein subunits.

Here's how the centrosome functions in the mentioned cellular processes:

1. Sensory reception: In sensory cells such as those found in the retina of the eye or in the inner ear, the centrosome plays a crucial role in organizing microtubules that help in the transport of sensory signals to the cell body for processing.
2. Locomotion: In motile cells such as sperm cells or certain immune cells, the centrosome is involved in organizing microtubules to form structures like flagella or cilia, which are essential for cell movement.
3. Embryogenesis: During embryonic development, the centrosome is vital for various processes such as cell division, cell migration, and establishment of cell polarity. It helps in organizing the microtubule cytoskeleton, which is essential for orchestrating these complex developmental processes.

Overall, the centrosome acts as a key regulator of microtubule dynamics and organization, influencing diverse cellular processes critical for the functioning and development of eukaryotic organisms.