Cis and trans isomers are positional isomers of a molecule. Consider something such as PtCl2Br2 which is a square planar complex Pt sits in the middle with each of the ligands (in this case the...
In the most simple sense, collagen is a protein. To be more specific, it is a polypeptide made up of of (3) amino acid based helices arranged in a triple right-handed helix, or coiled coil.