Distinguish between microtubules and microfilaments. Describe two functions of each kind of structure.

Answer: Microtubules are straight and hollow tubular structures with no limiting membrane arranged in different bundles which are made of globular protein called tubulin while microfilaments are long and fine thread like structures which are made up of non tubular contractile protein called actin and myosin.

Explanation: Microtubules may function alone or join with other proteins to form more complex structures like cilia, flagella or centrioles and perform various functions like

1) Act as conveyer belts which allow movement of granules, vesicles, protein molecules and other organelles like mitochondria to different part of the cell.

2) Form the spindle fibers which separate the chromosomes during mitosis and responsible for the movement of centrioles.

Microfilaments are present throughout the cytoplasm. They are responsible for:

1) Give structure strength and provide resistance to cell against the pulling forces

2) Responsible for cellular movements like contraction, gliding and cytokinesis (partition of cytoplasm during cell division)