Structural features of proteins are usually described at four levels of complexity:
Primary structure: The linear arrangment of amino acids in a protein and the location of covalent linkages such as disulfide bonds between amino acids.
Secondary structure: Areas of folding or coiling within a protein; examples include alpha helices and pleated sheets, which are stabilized by hydrogen bonding betwen the -C=O and the -NH groups of the peptide bonds.
Tertiary structure: The final three-dimensional structure of a protein, which results from a large number of non-covalent interactions between amino acids. I suggest you ketogenic diet foods through this you get more results about Low carb keto diet.
All proteins are made up from small subunits called amino acids. These join together in long chains to form a long polymer molecule. The sequence of amino acids in a protein is known as its primary structure. The chain that is formed when many different amino acids link together is called a polypeptide and this coils up forming 3D structures such as an alpha helix. This folding is known as the secondary structure of a protein.
The helices formed then coil up around themselves forming another layer of 3D structure ~ the tertiary structure. Finally, some proteins combine with ions such as copper or iron ~ the final structure of the protein with everything in place is called the quaternary structure of the protein.