Each centriole is surrounded by dense amorphous protoplasmic masses called massules.

The Structure of Centrioles

Centrioles are cylindrical structures found in animal cells, usually located near the nucleus. They are composed of microtubules, which are made up of the protein tubulin. Centrioles are typically arranged in pairs, perpendicular to each other, and form the core of the centrosome. The centrosome plays a crucial role in cell division, as it is responsible for organizing the microtubules that form the spindle fibers during mitosis.

The Role of Centrioles

Centrioles have several important functions in the cell. They are involved in the formation of cilia and flagella, which are hair-like structures that extend from the cell surface and are involved in cell movement and sensory functions. Centrioles also play a crucial role in cell division, as they are responsible for the separation of chromosomes during mitosis and meiosis.

Surrounding Protoplasmic Masses

Surrounding each centriole, there are dense amorphous protoplasmic masses called massules. These structures are not well understood and their exact function is still unclear. However, it is believed that massules may be involved in the regulation and organization of the centriole and centrosome.

Other Answer Options

The other answer options provided in the question are not correct:

a) Cytoplasmic particles: This term is too broad and does not specifically refer to the dense protoplasmic masses surrounding centrioles.

b) Meta-molecule: This term is not commonly used in the context of centrioles and does not accurately describe the structures surrounding them.

c) Cell granules: Cell granules are small, membrane-bound structures found in the cytoplasm of cells. They are not specifically related to centrioles.

Therefore, the correct answer is option 'D' - massules.