Question

The main structural features of proteins is_________.

Answer 1

We know that there are two main sources of proteins. They are based on animals and plants. There are various types of proteins based on their functions: digestive enzymes, transport, defense, structural, hormones, contractile, storage. Proteins are very essential for the growth of the body and repair in the parts of the body.

Complete answer:
Proteins are a group of macromolecules which perform a wide range of functions for the cell. They help in the metabolism by providing structural support and even by acting as enzymes, carriers, or hormones. Amino acids are the building blocks of proteins. A complete twenty different amino acids exist in proteins and hundreds to thousands of those amino acids are attached to each other in long chains to make a protein. Lipid could also be considered organic substances relatively insoluble in water, soluble in organic solvents (alcohol, ether etc.) actually or potentially associated with carboxylic acid and utilized by the living cells.
They act as antibodies that bind to specific foreign particles, such as viruses or bacteria, to help protect the body. They act as enzymes by carrying all of the chemical reactions that take place in the cells. Proteins which work as transport proteins carry atoms and tiny molecules within cells and throughout the body.
Therefore, proteins are linear polymers formed by linking the carboxyl group of one amino acid to the amino group of another amino acid with a peptide bond.

Note:
Remember that Lipids are molecules that contain hydrocarbons and make building blocks of structure and performance of living cells. Fats, Oils. Waxes, certain vitamins are examples of lipids. Most of the cell walls aren't made from proteins.