In most organisms, the living material contains 80% of proteins. Proteins are large, complex molecules made up of smaller units called amino acids. They play a crucial role in the structure and function of cells and are involved in various biological processes.

The high percentage of proteins in living material is due to their importance in maintaining the structure and function of cells and tissues. Proteins are the building blocks of cells and are responsible for many essential functions, including:

1. Structural Support: Proteins provide structural support to cells and tissues. They form the framework of the cell, giving it shape and stability. For example, collagen is a protein found in connective tissues that provides strength and support to the skin, tendons, and bones.

2. Enzymes: Proteins act as enzymes, which are biological catalysts that speed up chemical reactions in the body. Enzymes are involved in various metabolic processes, such as digestion, energy production, and DNA replication.

3. Transport: Proteins are involved in the transport of molecules across cell membranes. For example, carrier proteins facilitate the movement of ions and molecules across the cell membrane, ensuring the proper functioning of cells.

4. Defense: Antibodies are proteins that play a vital role in the immune system. They recognize and neutralize foreign substances, such as bacteria and viruses, preventing infections and diseases.

5. Cell Signaling: Proteins are involved in cell signaling pathways, which regulate various cellular processes. Signaling proteins transmit signals from the cell surface to the nucleus, triggering specific responses within the cell.

6. Movement: Proteins are responsible for muscle contraction and movement. Actin and myosin are two proteins involved in muscle contraction, allowing organisms to move and perform physical activities.

Overall, proteins are essential for the structure, function, and regulation of organisms. They are involved in a wide range of biological processes and are crucial for the survival and proper functioning of cells and organisms.