Question

Cross bridges between peripheral microtubules of cilia and flagella are made up of motor protein ___________.

• A. Myosin
• B. Actin
• C. Dynein
• D. Keratin

Hint:

Dynein arms are responsible for the bending movement of cilia and flagella.

Answer 1

The Correct Option is C

Step 1: Understanding cilia and flagella structure.
Cilia and flagella possess a 9 + 2 arrangement of microtubules. The peripheral microtubules are connected by cross-bridges that help in movement.
Step 2: Role of dynein.
Dynein is a motor protein that forms cross-bridges between adjacent microtubules and generates sliding movements using ATP.
Step 3: Analysis of options.
(A) Myosin: Incorrect — involved in muscle contraction.
(B) Actin: Incorrect — forms microfilaments, not microtubule bridges.
(C) Dynein: Correct — motor protein of cilia and flagella.
(D) Keratin: Incorrect — structural protein of epithelial cells.
Step 4: Conclusion.
The cross-bridges are made up of the motor protein dynein.