3.Understand the structure & functional applications of cell surface specialisations/modifications of structure such as microvilli, cilia & cytoskeleton.

Sure, let's break down the structure and functional applications of cell surface specializations/modifications such as microvilli, cilia, and cytoskeleton.

1. Microvilli: These are tiny, finger-like projections that extend from the plasma membrane of certain cells, such as those in the small intestine. They increase the surface area of the cell, allowing for greater absorption of nutrients. Each microvillus contains a core of actin filaments that help maintain its shape.

2. Cilia: These are hair-like structures that extend from the surface of many types of cells. They are involved in cell movement and in moving substances along the surface of the cell. For example, cilia in the respiratory tract help move mucus and trapped particles out of the lungs. Each cilium is supported by a cytoskeleton made of microtubules arranged in a specific pattern.

3. Cytoskeleton: This is a network of protein filaments and tubules that extends throughout the cytoplasm of a cell. It provides structural support, helps in cell division, aids in cell movement, and plays a role in transporting substances within the cell. The cytoskeleton is composed of three main types of fibers: microtubules, microfilaments (such as the actin filaments in microvilli), and intermediate filaments.

In summary, these cell surface specializations/modifications play crucial roles in cell structure, movement, and function. They allow cells to interact with their environment, absorb nutrients, move substances, and maintain their shape.