Proteins

1. Describe the detailed structure of proteins that enables this group of macromolecules to carry out diverse essential internal functions within cells and important interactive functions among cells. Then discuss the many different types of proteins, including structural proteins, scaffold proteins, enzymes, membrane transport proteins, regulatory proteins, and motor proteins.

Proteins are polymers made up of amino acids. They are the building blocks of all cells. Nitrogen is central to all the amino acids; they also consist of a carboxyl group and an amino group. There are 20 amino acids; histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.

The primary structure of proteins consists of these amino acids forming a chain (peptide bond) based on the gene they are working on. The secondary structure of proteins is when the chain begins to fold and coil utilizing hydrogen bonds. The coils and folds are alpha helices and beta-pleated sheets. Next, the tertiary structure is made when side chains of amino acids bind to the secondary structure. The tertiary structure provides stability for the protein. What bonds happen in the tertiary structure? The answer: hydrogen, ionic, hydrophobic, and covalent bonds. Some proteins have a quaternary structure that adds polypeptide subunits and then a single functioning unit is formed. Two kinds of quaternary structures are globular and fibrous. Globular are water soluble and spherical, like hemoglobin. Fibrous structures that are water insoluble and resemble threadlike fibers, like collagen.

The amino acids determine the shape of the protein, the shape gives rise to the function, the function is then determined by the proteins’ ability to bind to a molecule. What does the binding do? Antibodies bind to foreign substances and work as protection. Enzymes are able...