A protein is a polymer macromolecule, meaning it's built from long chains of amino acids. These chains, which also include hydrogen, oxygen, carbon, and nitrogen, usually contains between 200 and 300 amino acids, although the peptides are much smaller and the titins are much larger. Titins are so large, in fact, that they can contain over 33,000 amino acids.
It's important to not confuse the protein that we eat with the proteins that support cellular function. A functions of every living cell rely on protein to make it happen, and even though eating a juicy steak is tasty, it's not the same thing as supporting cellular life. There are three types of proteins: fibrous, globular, and membrane. Each type serves different functions and has a different makeup, but they are all built on the same components that form all proteins.
1. Fibrous Proteins
Fibrous proteins are just what they sound like. They are composed of long strings of individual fibers the bundle together to form a more solid "wall" of protein. These bundles form the muscles, tendons, bones, and other connective tissues in animals. These specific proteins include actin, collagen, elastin, keratin, myosin, tubulin, and many more.
2. Globular Proteins
Globular proteins are easy to remember because the word sounds like, "glob," and a glob of water is all it takes to break down these proteins. They are far more readily water soluble than the other types of proteins, which is helpful because their job is to transport and regulate substances. Some of the globular proteins are albumins, alpha globulin, carboxypeptidase, ependymin, fibrin, hemoglobin, integrin, myoglobin, selectin, thrombin, and von willebrand factor.
3. Membrane Proteins
These proteins get their name from their specific jobs in which they interact with the cell membranes within the organism when they serve as transporters for molecules, a bridge that allows interactions between two cells, or when they relay signals within the cell. Membrane proteins are interesting because more than half of the pharmaceuticals on the market today work by affecting the membrane proteins in some way, and because scientists believe that between 20% and 30% of all the genes in the genome work to encode the membrane proteins. That makes them pretty important to cellular function, and therefore, life itself. Some of these membrane proteins include hormone receptors, hydrolases, transferases, and many more.
Function of Ribosomes
Function of Nucleolus
The Function of Endoplasmic Reticulum
The Function Of a Cytoskeleton
The Function Of Golgi Apparatus
Frederick Sanger Facts