What are Cilia?

What are Cilia?

• A. Cilia
• B. Bristles
• C. Suckers
• D. Mollusk

Answer: (A)

Cilia are tiny, hair-like projections that extend from the surface of many cells. They can move in coordinated waves to push mucus and debris out of airways or to move fluids over tissues, and some cilia serve as sensory antennas for signaling. There are two main kinds: motile cilia, which beat rhythmically, and primary (non-motile) cilia, which detect chemical and mechanical signals to help regulate cell processes. The movement of motile cilia comes from microtubules arranged in a 9+2 axoneme, with dynein motor proteins producing the bending motion that creates the wave-like beat. This helps explain how cells can propel themselves or clear passages, as in the respiratory tract or fallopian tubes. Bristles are simple external hairs on some organisms and don’t have the specialized microtubule-based beating; suckers are adhesive attachments, and mollusk refers to an entire group of animals, not a cellular projection.