The tertiary structure of a polypeptide refers to the spatial arrangement of the amino acids that are found far away from one another in that polypeptide chain. Now, said another way, the poly, the tertiary structure of the polypeptide is simply the three dimensional arrangement of atoms, the three dimensional shape that the polypeptide chain will take within in its local environment. Now, the next question is what exactly are the factors, what are the interactions that play a role in creating and forming that tertiary structure of the polypeptide? So by far the most important factor, the driving force that forms the tertiary structure, is the hydrophobic effect and hydrophobic interactions. Now, that's because the majority of the proteins inside our body and inside our cells fold and create the tertiary structure in an aqueous solution, in a solution where water is the dominant solvent molecule. Now, we also have vanderballs interactions, disulfide bridges, hydrogen bonds and ionic interactions that also play a role in forming the tertiary factor.