The Raman spectra of cells studied here are rich in contributions from proteins, nucleic acids, lipids, and carbohydrates and we have succeeded in making assignments of all major peaks. The peaks at 619, 642, 745, 848, 1000, 1029, 1175, 1206, 1606, and are attributed to the various vibrations in aromatic amino acid (tyrosine, phenylalanine, and tryptophan) residues of proteins. The stretching vibrations of proteins are observed at 1029, 1059, , whereas the stretching of protein back bone is expressed at 934 and . The prominent deformation and amide I bands are visible at 1449 and , respectively, whereas the amide III peak is observed at . The peaks at 642 and can also be attributed to the stretching vibrations of cysteine residues in gauche and trans conformations, respectively.