Q.What are trichomes ? Write their functions.

Trichocysts of Ciliates

Even a single-celled organism has to defend itself and hold its ground while feeding. Paramecium, the familiar slipper-shaped ciliate, does this with tiny, specialised structures packed just under its surface — the trichocysts. They are a neat example of how much functional machinery can be built into one cell.

Where they are and what they look like

Trichocysts are small, spindle-shaped organelles embedded in the pellicle — the firm but flexible outer covering of a ciliate such as Paramecium. They are arranged in rows throughout the pellicle, ready to be discharged when needed.

What they do

When the organism is stimulated — for example, threatened by a predator or disturbed — the trichocysts discharge, shooting out long, sticky threads from the cell surface. These discharged threads serve two main purposes:

• Defence: the fired threads help ward off or entangle a predator or an attacker, protecting the cell.
• Anchorage during feeding: they can be discharged to anchor the body to a surface so the organism stays in place while it feeds.

Once discharged, trichocysts are typically replaced by the cell, so the animal is rearmed for future use.

Why this is interesting …